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diff --git a/debian-java-faq/debian-java-faq.sgml b/debian-java-faq/debian-java-faq.sgml new file mode 100644 index 0000000..e1f7cbb --- /dev/null +++ b/debian-java-faq/debian-java-faq.sgml @@ -0,0 +1,1830 @@ +<!doctype debiandoc system> + +<book> + +<titlepag> +<title>Debian GNU/Linux Java FAQ.</title> +<author> +<name>Javier Fernández-Sanguino Peña </name> +<email>jfs@debian.org</email> +</author> +<version>$Revision: 1.57 $ +<date>Sunday, 4th November + +<abstract> +Answers to Frequently Asked Questions on Debian and Java +(Note: some information is not up-to-date). Any changes/corrections to this +FAQ are appreciated. Please send them to the current maintainer as +described in <ref id="bugs">. +</abstract> + +<copyright> +This document may be freely redistributed or modified in any form +provided your changes are clearly documented. + +This document may be redistributed for fee or free, and may be modified +(including translation from one type of media or file format to another +or from one spoken language to another) provided that all changes +from the original are clearly marked as such. +</copyright> + + +</titlepag> + + +<toc> + + +<chapt>Introduction +<p> + +<sect>Introduction to this FAQ + +<P>This FAQ was started by Javier Fernández-Sanguino who on +February 1st, 2000 was (bold?) enough to send a message to the debian-java +mailing list with the subject "How about a Debian-Java-FAQ?". Of +course, since "every idea is a responsibility" he had to do this himself +looking through the three month-long archive of the newborn mailing list. + +<p>The purpose of this FAQ is to be a place to look for all kinds of +questions a developer or user might have regarding Java as far as Debian +is concerned. It includes license issues, development packages available, +and programs related to building a Free Software Java environment. + +<p>Thanks go to all the (many) contributors from the debian-java mailing list, +who have made this document possible. Without their knowledge this +FAQ would not be at all possible since I only have a vague knowledge +of what they're talking about when I browse the list. + +<p>Special thanks go to Paul Reavis, whose previous Debian-JDK +informational page I used to add more information, and who made useful +suggestions to this document. Also to Peter Moulder who revised +thoroughly the FAQ and provided many suggestions, to Juergen +Kreileder, maintainer of Blackdown's debian packages who pointed out +some mistakes, and to Egon Willighagen, who has provided quite a lot +of proper patches to update its content. + +<p>This document does not address issues with other Linux +distributions, or with non-Debian-specific problems. See the <url +id="http://www.blackdown.org" name="Blackdown pages"> for +information on these. More specifically you might want to check out the +<url id="http://www.blackdown.org/java-linux/docs/support/faq-release/FAQ-java-linux.html" name=" java-linux@java.blackdown.org FAQ"> written by Stephen M Wynne +(last updated january 2000 as of this writing). Another useful +source of general information might be the +<url id="http://www.jguru.com/faq/Linux" name="Java on Linux FAQ"> maintained +by Nathan Meyers. + + +<sect>Location of this FAQ + +<p>This FAQ is published under the Debian Documentation Project +at <url id="http://www.debian.org/doc/manuals/debian-java-faq/">. +The <package>java-common</package> (available at +<url id="http://packages.debian.org/java-common">) provides an +HTML version for offline reading. The package version does not provide Text and +PDF versions currently (if you want them please submit a bug +'wishlist' to the package). Also, the web version might be more up-to-date +than the package's offline version. + +<sect id="bugs">Sending bugs on this FAQ + +<P>Please note that this FAQ is slightly out of +date and is seeking an active maintainer. If you are willing +to maintain it and are knowledgeable about Java in Debian, +please contact the current maintainer. In any case, fixes to information +that is not up to date are welcome (patches against the latest +<url id="http://cvs.debian.org/ddp/manuals.sgml/java-faq/?cvsroot=debian-doc" +name="CVS sources"> are even better). + +<p>In any case, if you want to send bugs on this FAQ please send them +to the current maintainer. However, make sure you are reading the +latest (english) version available at <url +id="http://www.debian.org/doc/manuals/debian-java-faq/index.en.html"> +Note that translations, if available, might also be slightly out of +date from the original, english, version. Check out the english +version first if you are reading a translation before sending a bug. + +<sect id="moreinfo">Complementary information + +<p>Users might want to access some online sources to complement the +information available in this FAQ which might be, sometimes, too out +of date. The main source of information is the +<url id="http://wiki.debian.org/Java" name="Java entry"> at the Debian's wiki. + +<p>Since Ubuntu is based on Debian, some users might find it helpful +to check the tips on <url id="https://help.ubuntu.com/community/Java" +name="Installing Java"> on Ubuntu's wiki. + +<sect id="pending">Uncovered issues + +<p>This FAQ does not describe some issues due to lack of time and/or +information. If you are able to help in any of these, please, provide +them to the documentation maintainer: + +<list> + +<item>Information on how to use <prgn>update-alternatives</prgn> to handle +Java and how <file>/etc/jvm</file> and <file>/etc/java</file>. + +<item>Information on how to setup a fully working Servlet engine (Application +Server) using Apache and Tomcat or information on how to setup non-free +application servers (such as WebSphere) in Debian. + +<item>Specific information targeted for non-i386 users (PowerPC users and AMD64 users), some can be found in Ubuntu's wiki. + +</list> + +<chapt>Introduction to Java + +<sect>What is Java? +<p> +Java is a strongly-typed platform-independent object-oriented programming +language often associated with the World Wide Web. Java was developed by +<url id="http://www.sun.com" name="Sun +Microsystems"> for embedded applications, but has since grown to become a +general-purpose programming language. Java source code can either be +compiled to a machine-independent byte-code that can be run by Java virtual +machines, or it can be compiled directly to executable code for any number +of platforms, including Linux, Win32, and others. + +<p>A common API, shipped with all Java development environments, +provides socket support, a graphical user interface widget set, graphical +drawing tools, standard IO, events, math, database interfaces, and +multithreading, to name a few. + +<p>The multithreading support can happen either in kernel threads or userland +threads, depending on the implementation of the Java virtual machine used. + +<p>Of course, Java is also the name of a popular island of Indonesia: +check out the facts at the <url id="http://www.gnu.org/software/java/java.html#TOCOriginalJava" name="GNU Java pages"> + +<sect>Why would I be interested in Java? +<p> +Java is widely used in large and small scale distributed, server, and client +applications. It's fun to use. The javadoc tool creates documentation from +comments in the code, so if you comment your code you get the docs for free. + +<sect>What is a JIT? +<p> +JIT is an acronym for Just In Time. It refers to a VM plugin to speed up VM +execution by compiling bytecode to native machine code. + +<sect>Where can I read more about Java? +<p> +Of course, <url id="http://java.sun.com"> would be the first place to +read information on Java, right from the company who started +it (i.e. Sun). However good places for Java and Linux could be: + + +<list> +<item>Sun's <url id="http://java.sun.com/linux/" name="Java Technology +on Linux"> pages. + +<item>Blackdown's <url id="http://www.blackdown.org/java-linux/docs/support/faq-release/FAQ-java-linux.html" name="Java and Linux FAQ">. + +<item>GNU's <url id="http://www.gnu.org/software/java/" name="Java software"> + + +<item>Enterprise in a Nutshell by Gary Meyer, at <url id=" +http://en.tldp.org/HOWTO/Enterprise-Java-for-Linux-HOWTO.html">. +Explains how to set up an environment including JDK, web server, Java servlets, +JDBC access to a database and EJBs. If you are interested read also +Java Enterprise in a Nutshell at <url +id="http://www.oreilly.com/catalog/jentnut/">. + + +<item>The <url id="http://www.linuxjournal.com/" name="Linux Journal Magazine">, +the following articles might be worth reading: +<list> +<item>Issue 105 <url id="http://www.linuxjournal.com/article.php?sid=4860" +name="Compiling Java with CGJ"> +<item><url id="http://www.linuxjournal.com/article.php?sid=6290" +name="Getting Started with Java on Linux"> +<item>Issue 94 <url id="http://www.linuxjournal.com/article.php?sid=5612" +name="Embedded Linux and Java--Wave of the Future?"> +<item><url id="http://www.linuxjournal.com/article.php?sid=4819" +name="Using and Writing Java Servlets"> +<item>Issue 66 <url +id="http://www.linuxjournal.com/lj-issues/issue66/3119.html" +name="Java servlets"> and <url +id="http://www.linuxjournal.com/lj-issues/issue66/3224.html" +name="Java 2 SDK">. + +</list> + +<item>The <url id="http://www.linuxgazette.com/" name="Linux Gazettej +Magazine">, the following articles might be useful: +<list> +<item>Issue 87 <url id="http://www.linuxgazette.com/issue87/jenkins.html" +name="A Keep-Alive Program You Can Run Anywhere"> +<item>Issue 69 <url id="http://www.linuxgazette.com/issue69/peda.html" +name="Installing Tomcat on Linux"> +<item>Issue 48 <url id="http://www.linuxgazette.com/issue48/lane.html" +name="Linux, Java and XML"> +<item>Issue 45 <url +id="http://tldp.org/LDP/LG/issue45/gibbs/Linux_java.html" +name="Setting Up A Java Development Enviroment For Linux"> +<item>Issue 33 <url id="http://tldp.org/LDP/LG/issue33/burtch.html"> +<item>Issue 32 <url id="http://tldp.org/LDP/LG/issue32/rojansky.html" name="Java and Linux"> +<item>Issue 25 <url id="http://tldp.org/LDP/LG/issue29/hamilton.html"> +</list> + + +<!-- No longer available +<item>Linux users worlwide includes information on how to use Java an +Linux <url id="http://linuxusers.webprovider.com">. +--> + +<!-- Pretty old and not very much maintainted ATM +<item>Linux Java Tips and Hints at <url +id="http://www.parnasse.com/java.shtml">. +--> + +<!-- no longer available +<item>The Java and Linux Page <url id="http://www.geocities.com/SiliconValley/Platform/8187/java/Linux_java.html"> +--> + +<item><url id="http://www.linuxfocus.org/" name="LinuxFocus">, a free +multilingual journal: +<list> + +<item>March 2003: <url +id="http://www.linuxfocus.org/English/March2003/article285.shtml" +name="Accessing PostgreSQL through JDBC via a Java SSL tunnel"> + +<item>January 1999: <url +id="http://www.linuxfocus.org/English/January1999/article78.html" +name="Programming with Java, part II"> + +<item>July 1998: <url +id="http://www.linuxfocus.org/English/July1998/article57.html" +name="Programming with Java, part I"> + +</list> + + +<item>The Java-CGI HOWTO from David H. Silber at <url +id="http://en.tldp.org/HOWTO/Java-CGI-HOWTO.html"> +explains how to set up your server to run Java CGIs. +Maybe it is worth looking at servlets. + +<item>Java Programming on Linux, by Nathan Meyers, website at +<url id="http://www.javalinux.net/">, which is a book devoted to the +topic of using Java on Linux (there's no online version of it, though) + +</list> + +Other sites regarding Java would be: +<list> +<item>The Java Lobby <url id="http://www.javalobby.org">. + + +<item>Brewing Java: a tutorial at <url +id="http://metalab.unc.edu/javafaq/javatutorial.html">. + +</list> + +If you are browsing the web for free Java information you can of +course use Google. If you are looking for applets with source code look at <url +id="http://javaboutique.internet.com/javasource.html">. Check also +<ref id="free"> for pointers to the free Java platforms available, which +might or might not be listed in GNU's webpages devoted to Java. + +<sect>Where can I ask questions about Java on Debian? + +<p>The appropriate place to ask such questions is <email>debian-java +at lists.debian.org</email>. You can subscribe at the <url +id="http://www.debian.org/MailingLists/subscribe" name="Mailing List +Subscription"> page. + + +<chapt id="debian-java-woody">Status of Java in Debian GNU/Linux 3.0 (Woody) + +<sect>Where is Debian Java going? + +<p>The first thing you should understand about the design strategy of Debian +is that our goal is to produce a 100% Free Software platform. In that +sense, some of the Java tools available +<footnote> +Notably Blackdown's port to Linux of Sun's Java Developer's Toolkit (SDK) or +Java's Runtime Environment (JRE). Which you should retrieve from Blackdown, +see <ref id="blackdown-pack">. +</footnote> +are not available in the standard Debian distribution for licensing reasons, +not for any technical motivation (see <ref id="license-concerns">). + +<p>That said, basically all of the technologies you might ask about can +be or are available for Debian immediately. In order to usefully +answer your questions, however, here you have a status from an Open +Source availability perspective. + +<p>If you are <em>really</em> interested, read the following: <url +id="http://lists.debian.org/debian-java/1999/debian-java-199912/msg00015.html"> +and <url +id="http://lists.debian.org/debian-java/1999/debian-java-199910/msg00017.html">. +This section is a summary of the information therein. +(<em>Note</em>: this information might not be fully updated at this point in +time, it was written around 1999) + +<sect>Is there a Java1 compiler (.java to .class)? +<p>There is the Kopi Java Compiler written +in Java. And the super fast Jikes written in C++. + +<p>Gcj can also compile .java to .class. CVS version currently +does handle inner classes, as well as any other jdk 1.1 constructs, +but might not be able to compile a complicated program like the +XSL processor xt. It is written in C, so is reasonably fast. +It generates reasonably good bytecode. And +of course being able to use the same compiler for .java to .class and +.java to native has its advantages. + + +<sect>Is there a Java1 JVM or JIT? + +<p>Kaffe 1.0.5 is largely feature complete and now includes support +for RMI. It is not clear as to whether Kaffe's serialization is +"binary compatible" with Sun's implementation in all cases so there +may be interoperation issues in some casses. Kaffe comes with a big +class library. + +<!-- No, it's not anymore +<p>Japhar is also available. +--> +<p>libgcj (the run-time library for gcj) now includes an interpreter +and ClassLoader. +<p>tya, a JIT compiler, is also available. + +<sect>Is there a Java1 native compiler? +<p>GCC, the Gnu Compiler Collection comes with GCJ, the Gnu Compiler for Java + +<sect1>Java2 native compiler +<p>It is unclear whether native compiler refers to the adaptive JIT + capabilities in Java2 or to a compiler that understands Java2 + semantics. In either case, Kaffe's JIT strategy is not adaptive but + performs correctly, and improving, it is believed IBM's Jikes + compiler understands Java2 concepts such as weak references. + +<sect>Does Debian have Java2 foundation libraries? + +<p>Many of these components have been cloned under a Free Software +license. Kaffe provides many of these routines, including an +up-to-date RMI implementation. There are, however, definitely +shortcomings. Swing, as far as we know, has not been cloned. + +<sect>Is there a Java Debugger (jdb equivalent)? +<p><package>jswat</package> + +<p>Gdb can debug native code produced by Gcj. Stuart Grossman (Cygnus) also +wrote support for Gdb to debug other VMs using JVMDI. This has not +been released, because the Gdb internals were changed at the same +time, and no-one has had time to re-integrate the changes. We can +probably get Cygnus to release the old code, if someone wants to look +into getting this stuff working with the current Gdb internals. (A +non-trivial job.) <p>See <url +id="http://sourceware.cygnus.com/java/gdb.html"> on how to debug +gcj-compiled Java programs. + +<sect1>What free edit-interactive/graphical debugging tools are available on +Debian? +<p>jde, ddd, more? + +<P>One of the some nice features of jde are autoindention and syntax +highlighting, but it also supports debugging and compilation. + +<sect1>Known problems + +<p>My version of <prgn>jdb</prgn> (jdb version 98/01/06) terminates +after a program finishes execution, and I have to reset every +breakpoint if I want to run through the program again. This makes +using jdb extremely frustrating. Jdb also can't (easily) print the +values in an array which is more than three elements long. Ddd lets me +work around both of these annoyances. + +<p><prgn>ddd</prgn> 3.1 and earlier would "hang" when receiving +certain prompts with wierd thread names from jdb. This made it very +hard to use ddd with jdb. This has been fixed in ddd 3.2. It doesn't +look like ddd 3.2 has been packaged yet. I suspect the current +packaged version of ddd won't work well with jdb. + + +<sect>Is there an Appletviewer tool? +<p>There are some alternatives for an appletviewer tool: + +<list> +<item>Blackdown's appletviewer (in jdk1.1). +<item>Kaffe's appletviewer. +<item>Ibm's appletviewer (in ibm-jdk). +</list> + +<sect>Is there a Jar tool? +<p><package>FastJar</package> which is indeed very fast. +<package>Kaffe</package> also has a jar tool. + + +<sect>Is there a Javadoc tool? +<p><package>doc++</package> can work with C++ and Java. Additionally, there +are the <package>gjdoc</package> and <package>gjdoc-native</package> packages. + +<sect>Does Debian do Enterprise Java Beans (EJB)? +<p>There is activity in this area, the most noteworthy being the Open + Source EJB implementation from Bull in France called Jonas. I have + done some work with this system and it provides a good start towards + a full EJB feature set. In particular, it provides a transaction + monitor and a container based persistance implementation. I have + used this system on Linux with free databases such as Postgresql. I + have not been able to get the system fully operational on Kaffe. + Additionally, the system depends on many Sun APIs which have not + been cloned (JTA, JNDI, and EJB itself). + +<sect>What is JAIN? +<P> + It seems to be a system for + controlling large scale, integrated communications infrastructures + and modeling events with such networks via the JavaBeans API. The + scale of this effort seems very large and encompasses the work of + many organizations. The work is very new and seems to tie into Sun's + SCSL strategy, which leads us me to believe that there is not + much in the way of Open Source options in this area. However, some + protocols such as H.323 are genuinely open and are even cloned so it + is possible that chunks of the JAIN system may exist in a scattered + manner. We have no knowledge of a serious Free Software + implementation of RTP or the H.323 infrastructures in Java. + +<sect>What is Jini? +<p> Jini presents an especially pronounced Free Software problem. Jini is + only available as source from Sun and that source is only available + under the SCSL. The SCSL is not compatible in any sense with either + the legal mechanics or the political spirit of Free Software. The + SCSL also makes cloning the API of an SCSL implementation illegal + which precludes even a clean room replication of Jini. If you are + interested in tuple space type implementations there are Open + Source options. + +<sect>Is there a full list of packages? + +<p>Below is a list given on packages that can be found in Debian 3.0 +(aka Woody). The list does not display which of these packages can be found +in main, and which is contrib or non-free. + +<list> + <item>Runtime environments/Virtual Machines + <list> + <item><package>jdk1.1</package> (Sun's JDK 1.1.8) + <item>IBM 's JDK 1.1.8 (installer package) + <item><package>kaffe</package> + <item><package>kissme</package> + <item><package>sablevm</package> + </list> + <item>Tools + <list> + <item>Compilers + <list> + <item><package>jikes</package> (also <package>jikes-1.14</package>, <package>jikes-gij</package>, + <package>jikes-kaffe</package>) + <item><package>jdk1.1</package> + <item><package>gcj</package> + <item><package>tya</package> (JIT compiler) + </list> + <item>Debuggers/Testing + <list> + <item><package>jswat</package> + <item><package>junit</package> + </list> + <item>IDE/Editors + <list> + <item><package>jedit</package> + <item><package>jde</package> + </item> + <item>Build tools + <list> + <item><package>ant</package> + <item><package>jmk</package> + <item><package>mmake</package> + </list> + <item>Other + <list> + <item><package>fastjar</package> + <item><package>jad</package> (decompiler) + </list> + </list> +<item>Ant +</list> +<item>Libraries + <list> + <item><package>lib-dom-java</package> + <item><package>lib-gnu.getopt-java</package> + <item><package>lib-gnu.regexp-java</package> + <item><package>lib-saxon-java</package> + <item><package>libavalon-excalibur-java</package> + <item><package>libavalon-framework-java</package> + <item><package>libbcel-java</package> + <item><package>libbsf-java</package> + <item><package>libcrimson-java</package> + <item><package>libcommons-beanutils-java</package> + <item><package>libcommons-collections-java</package> + <item><package>libcommons-digester-java</package> + <item><package>libjdom-java</package> + <item><package>libjunitperf-java</package> + <item><package>libldap-java</package> + <item><package>liblog4j</package> + <item><package>liblogkit-java</package> + <item><package>libnbio-java</package> + <item><package>liboro-java</package> + <item><package>libpgjava</package> + <item><package>libreadline-java</package> + <item><package>libregexp-java</package> + <item><package>libservlet2.3-java</package> + <item><package>libservlet2.2-java</package> + <item><package>libsoap-java</package> + <item><package>libtomcat4-java</package> + <item><package>libxalan-java</package> + <item><package>libxalan2-java</package> + <item><package>libxerces-java</package> + <item><package>libxerces2-java</package> + <item><package>libxt-java</package> + </list> +</list> + +<chapt id="debian-java-sarge">Status of Java in Debian GNU/Linux 3.1 (Sarge) + +<sect>Are there many changes? +<p> +Yes, quite some. There have been very interesting developments +in Debian Java lately. Slowly, there seem be developed a set of +Debian tools to deal with maintaining Debian package of Java +applications and libraries. +At this moment, there only seems to be dh_javadoc, which is a tool +in the <package>gjdoc</package> package. However, people spoke about +other tools on the debian-java mailing list in 2003. + +<p> +In addition to this, <package>ant</package> has found its way into main, +paving to way for other packages to enter main. + +<p> +And the <package>eclipse</package> seems to get rather stable. Early +August 2003, the gcj team even was able to compile the IDE to native +code, using only minor modifications. + +<p> + It is quite useful to first browse the section on Java in Debian + GNU/Linux Woody (since those in woody are also in later releases, see + <ref id="debian-java-woody">), + but there are somes changes. Instead of listing all the + packages again, this section will list only changes: + +<list> + <item><package>eclipse</package> An extensive IDE + <item><package>sablevm</package> A free Virtual Machine + <item><package>free-java-sdk</package> A free Java SDK (compiled from DSFG compliant Java tools) + <item><package>libgnome0-java</package> Java bindings to Gnome GUI library + <item><package>gjdoc</package> A Javadoc 1.3 replacement (90% of Doclet API implemented) + <item><package>kaffe</package> Release 1.1.3 can run much more software than 1.0.5 in woody + <item><package>ant</package> Version 1.6 is in main +</list> + +<p> +The following packages are no longer in testing/unstable: +<list> + <item><package>libswing-java</package> Which is mentioned here: <ref id="sect:dfsg-compliant-gui">. +</list> + +<chapt id="debian-java-etch">Status of Java in Debian GNU/Linux 4.0 (Etch) + +<p>The <em>Etch</em> release was the first one to provide Sun's JDK +environment without the need to download it from third-party repositories +(see <ref id="java56">). + +<p>As part of the effort to move Java packages to main, 36 new Java packages +were moved to main after being built with free Java development tools. Notably, +<package>ant</package> (a Java-based build tool), +<package>libstruts1.2-java</package> (a MVC framework), +<package>tomcat5</package> (a Java servlet engine) and +<package>eclipse</package> (a developer's environment platform) have been moved +to main. For the full list see the <url +id="http://wiki.debian.org/Java/AlreadyMovedToMain" name="Debian wiki">. + +<sect>Which Java package are currently in main? + +<p> +At the time of writing, 209 Java packages were found in main, of which 119 were +Java libraries. To see the list of packages in main (i.e., not contrib and +non-free), try: + +<example> +grep-available -F Depends -sSection,Package java | paste -sd " \n" | \ + grep -v contrib | grep -v non-free | sort +</example> + +<p>There are additional packages in the <em>contrib</em> section which can be +found with a command similar as the one above. + +<p>The <url id="http://pkg-java.alioth.debian.org/" name="pkg-java"> +website also maintains a list (probably more up to date) of java +packages. + +<sect>What keeps Java packages out of main? + +<p>An overview of packages that are still not in main is found at the +Debian Wiki site: <url id="http://wiki.debian.org/Java/MoveToMain" +name="MovingToMain">. + +<p>The current status, as of this writing (june 2004) is that there is +progress of moving packages that use Java but can be run without the +aid of non-free software from contrib to main. A number of packages +have been moved to main and new releases of GNU Classpath, SableVM, +and Kaffe promise further steps ahead. Two of the major issues +currently being looked at are making gjdoc a proper javadoc +replacement and building ant with Free Software only. People wanting +to help can start by inspecting packages labeled as unknown on the +<url id="http://wiki.debian.org/Java/MoveToMain" name="Java to main wiki"> + +<sect>What can I expect in future releases? + +<p>In November 2006 Sun announced that Java would be open sourced under the GPL +and provided source for the javac compiler and HotSpot virtual machine. +Sun published their Java sources under the name OpenJDK. Some 4% are missing +from the sources, for which Sun has not the copyright themselves. The remainder +of the JDK source will be published in 2007. Debian has a roadmap to publish +all of Sun's opensource Java technologies as described in the <url +id="https://penta.debconf.org/~joerg/events/126.en.html" name="Debconf7 talk: +OpenJDK and the Free Java Packaging Roadmap">. + +<chapt>Java Development +<p> +<sect>What full-fledged Java development platforms are available in Debian? + +<p> If you are looking for an integrated, java virtual machine, +compiler and runtime environment Debian does provide them. Of course +that would depend on the Debian GNU/Linux version you are using, +generally speaking they would be: + +<list> +<item>Sun's jdk 1.4 (port made by Blackdown, see <ref id="blackdown-pack"> or +go to <url id="http://www.blackdown.org">) + +<item><prgn>kaffe</prgn>. + +<item>Sun's Java 5 jdk, available in the Debian 4.0 <em>etch</em> release in the +<em>non-free</em> section. + +<item>Sun's Java 6 jdk, available in Debian <em>lenny</em> (unreleased, +currently testing) and Debian <em>sid</em>, also as packages in the +<em>non-free</em>. + +</list> + +<p>Previous release of Debian included an installer package for IBM's Java +Development Kit, but that is not longer available. + +<p>Since the Debian 3.1 'sarge' release, Debian provides the +<package>free-java-sdk</package> package which makes up a free Java Software +Development Kit (SDK). All software it depends on are DFSG compliant. + +<sect id="free">What free platforms are there and how can I contribute? +<p> +Please help one of the Free Java implementations if you want to use Java +in Debian. There are a lot of projects that you can choose from: +<list> + +<item>kaffe: <url id="http://www.kaffe.org">. + +<!-- No longer there +<item>Japhar: <url id="http://www.japhar.org">. The Java virtual +machine of "Hungry Programmer". More info in <url +id="http://www.hungry.com/products/japhar">. +--> + +<item>gcj and libgcj: <url id="http://sourceware.cygnus.com/java/"> + +<item>jikes: <url id="http://www.research.ibm.com/jikes/">. A fast +compiler written in C++ (check also <url +id="http://www10.software.ibm.com/developerworks/opensource/jikes/">). +(The new license seems to be finally really free) + +<item>kopi: <url id="http://www.dms.at/kjc/">.Yet Another Free Java +Compiler, this time written in Java, and GPL. Included in Kaffe since +release 1.0.5. + +<item>FastJar <url id="http://fastjar.sourceforge.net/">, as a jar +tool. (this link seems to be broken, anyone?) + +<item>Classpath <url id="http://www.gnu.org/software/classpath/"> or +<url id="http://www.classpath.org">. Most of the Standard classes for +Java 1.2 (except Swing and RMI) are implemented by the ClassPath +project, it tries to build an alternative to jdk's 1.2 core classes. + +<item>Most of the RMI classes are implemented by NinjaRMI +<url id="http://www.cs.berkeley.edu/~mdw/proj/ninja/ninjarmi.html"> + +<item>Autoconf macros <url +id="http://www.internatif.org/bortzmeyer/autoconf-Java/"> helps easy +recompilation of Java programs. <item>Mauve <url +id="http://sourceware.cygnus.com/mauve/"> is a free suite to test if +these tools are 'compliant'. + +</list> + +<p>Most free Java development is grouped under the <url +id="http://www.gnu.org/software/java/" name="Free Java +Project">. There is a list on free Java at <url +id="http://www.lists.deus.net/mailman/listinfo/free-java">. + +<sect id="license-concerns">Questions on platforms and license concerns + +<sect1 id="java56">Java 5 and 6 + +<p>There are binary packages available for the Java 5 platform +for both Debian 'lenny' (currently, the <em>testing</em> distribution) and +Debian Sid, and binary packages for Java 6. These packages are available in the +<em>non-free</em> section, so you have to configure your apt sources appropiately. If +you have the following in your <file>/etc/apt/sources.list</file>: + +<example> +deb http://ftp.debian.org/debian etch main +</example> + +you need to change it to: + +<example> +deb http://ftp.debian.org/debian etch main contrib non-free +</example> + +Once this is done and you have updated your package database. You can either +install the Java development kit: + +<example> +apt-get install sun-java6-jdk +</example> + +or the Java runtime environment: + +<example> +apt-get install sun-java6-jre +</example> + +<p>If you are using the Debian 4.0 'etch' release you will find Java 5 instead. +Similarly, you can install the Java development kit: + +<example> +apt-get install sun-java5-jdk +</example> + +or the Java runtime environment: + +<example> +apt-get install sun-java5-jre +</example> + +<p>Sun recommends you update the alternatives system to have Sun's tools as the +default: + +<example> +update-java-alternatives -s java-6-sun +</example> + +Or for java 5: + +<example> +update-java-alternatives -s java-1.5.0-sun +</example> + +<sect1>Sun's OpenJDK + +<p>Sun adopted in november 2006 the GPL library for almost all of the virtual +machine and GPL v2 + the <em>Classpath exception</em><footnote>This is similar +to GCC linking exception in that it allows non-GPL code to be linked with the +GPL code. This exception was developed by the <url +id="http://www.gnu.org/software/classpath/license.html" name="Classpath +project"></footnote>for the class libraries and those parts of the virtual +machine that expose public APIs. + +<p>As a consequence, the free OpenJDK code might be available in Debian in next +releases. + +<p>For more information see <url id="http://www.sun.com/software/opensource/java/faq.jsp" name="Free and Open Source Java">. + +<sect1>Java 2 SE (aka JDK1.2) +<p> +<sect2>Why is Sun's Java 2 SE (aka jdk 1.2) not available? + +<P>Due to license problems. Clause 2 of the <url +id="http://www.sun.com/software/communitysource/java2/license.html" +name="license"> (check also the <url +id="http://www.sun.com/software/communitysource/faq.html" name="FAQ">) +that comes with is says: + +<example> +Software is confidential and copyrighted. Title to Software and all +associated intellectual property rights is retained by Sun and/or its +licensors. Except as specifically authorized in any Supplemental License +Terms, you may not make copies of Software, other than a single copy of +Software for archival purposes. +</example> + +<sect2 id="scsl">What are the problems with Suns' new license? +<p>Sun has moved to a new license the <em>Sun +Community License</em>, like the GPL it is a viral license, but making +all it touches subject to Sun licensing fee. The SCSL even goes so far as to +define any implementation of a Sun specification as a "Modified Work". +Basically, this means that if you implement any part of the new 1.2 API +or Jini API, even from scratch, Sun will "own" your implementation and you +will have to pay them for the right to use it. +<example> +13. "Modification(s)" means (i) any change to Covered Code; + (ii) any new file or other representation of computer + program statements that contains any portion of Covered + Code; and/or (iii) any new Source Code implementing any + portion of the Specifications. +</example> +<sect2> What is the SCSL? +<P> + The SCSL is the "Sun Community Software License" that can be found + <url id="http://java.sun.com/communitysource/">. It is not + compatible with Free Software for several reasons, and agreeing to + this license (e.g. by downloading source covered by the SCSL) will + make it impossible for you to contribute to free software clean-room + implementations. According to Sun, this includes using documentation + and API specifications available only under SCSL. + +<P>To quote one open source developer, the SCSL is "about as + free as the former Soviet Union". + +<p>However, if you have never agreed to the SCSL, then it is still +permissible, barring any patents that Sun has for the technology, +for you to create your own clean room version of the 1.2 API. It is +important that you never agree to the license, even for the +documentation. For example, if you buy a printed book which +describes the API, there is a long legal history (in the US at +least), that prohibits attaching these kinds of contracts to books. + +<sect2>Can I use jdk1.2 while working with the free Java implementations? +<p> + Clause 1 of the Supplemental License Terms says: +<example> + [You] may not create, or authorize your licensees to create + additional classes, interfaces, or subpackages that are contained in + the "java" or "sun" packages or similar as specified by Sun in any + class file naming convention; +</example> +<p>Which seems to prevent one from making his own implementation of the +standard Java classes using the JDK. +<P>However, it is unclear whether or not the word `additional' includes +reimplementations of existing classes, or whether it applies only +to classes with new names. + + +<sect2>Why is (some) free software not implementing Java2? +<P> + Sun has made public statements in connection with their legal + strategy in the Sun-Microsoft lawsuit that indicate that the + company considers the published specifications of Java2 to be + intellectual property that can not legally be used by persons + involved in efforts to create Java2 clean-room implementations. + For this reason, some open source projects have decided to not + implement Java2 any time soon. One example is Kaffe. Some + projects (like the Classpath project) have decided to + challenge Sun's legal position and are going ahead with Java2. + + +<sect1 id="ibm-jdk">IBM's Developer Kit for Linux +<P> +<sect2>Can Debian distribute IBM's jdk? + +<p>No, as its license does not allow redistribution. Actually, older releases +(version 1.1) even restricted use of the jdk to specific distributions (and +Debian was not included in the list). + +<p>You can still download it and use it in Debian yourself even Debian +is not in the list of tested (or supported) platforms, see +<url id="http://www.ibm.com/developerworks/java/jdk/linux/">. + +<sect2>Is it possible to obtain a licence for Debian? + +<p>It would still be non-free, because of item 8 in the <url +id="http://www.debian.org/social_contract#guidelines" name="Debian Free Software +Guidelines">: "License Must Not Be Specific to Debian". + +<sect1>JRE +<p> +<sect2>Can Debian distribute JRE? +<p> +(Quoted from Gene McCulley <url +id="http://lists.debian.org/debian-java/1999/debian-java-199908/msg00021.html">) +I don't think we can or want to distribute the JRE with Debian. +The supplemental license terms of the JRE has a few very nasty clauses: +<example> + 1. License to Distribute. You are granted a royalty-free right to + reproduce and distribute the Software provided that you: (i)distribute + the Software complete and unmodified, only as part of, and for the + sole purpose of running, your Java applet or application ("Program") + into which the Software is incorporated; +</example> +<p>We might get away with this one since we distribute it together with +Java applications bundled with Debian. But we also do want to allow people +to download only the jre package. +<example> + (ii) do not distribute additional software intended to replace any + component(s) of the Software; +</example> +<p>But we cannot agree to this one. We want to distribute Kaffe, Japhar, +Classpath, Gcj, Kopi, Fastjar, etc which are intended to replace the JRE +with a Free version. Even if we don't consider non-free part of Debian +(the JRE would not go into main :) I think we should not encourage software +that tries to prevent Free replacements. +<example> + [...] (v) may not create, or authorize your licensees to create additional + classes, interfaces, or subpackages that are contained in the "java" or + "sun" packages or similar as specified by Sun in any class file naming + convention; +</example> +<p>My example why this is a bad clause was not so good since someone pointed +out that you do not want to create something that is non standard. I do +agree that we want a standard implementation of the core classes, but I +also think that you should have the freedom to create non-standard classes. +(Or fix bugs or stupid mistakes in the standard classes.) +<example> + [...] and(vii) agree to indemnify, hold harmless, and defend Sun and its + licensors from and against any claims or lawsuits, including attorneys' + fees, that arise or result from the use or distribution of the Program. +</example> +<p>And I don't think that Debian (or SPI) can or wants to do that. + +<p>So I am afraid that we also cannot distribute the Sun or Blackdown JRE. +This isn't that bad since it is non-free software, but it is annoying. +As I said before please help one of the (many) Free Java projects out there +if you want to see a Free JVM, Standard Classes, Compiler, etc. in Debian. +They are far from complete but they do work for most purposes + +<sect1>GPL or LGPL? +<p> + Java uses dynamic linking at runtime. Using the reflection + API and class loading, the linking can be completely data + driven, specifying classes and methods by name. This moves + the legal issues of using GPL'ed Java code into the user's + hands, as a violation of the GPL can not be proven from the + executable itself. Unlike plugins, Java classes do not even + have to have a specific structure to be used in such ways. + By using native methods and selecting DLL's at runtime, + this problem might also affect native code. +</P> +<P> + Example: a GPL'ed Java dependency checker using the + reflection API. Java's runtime linkage, in particular the + reflection API, blurrs the lines between code and data + even more than e.g. native plugins. +</P> +<P> + If you want to write Java code that can be used without + the user having to worry about licensing issues, consider + using the Lesser GPL (LPGL). If you want to avoid seeing + your classes and packages being used by non-free software, + consider using the GPL license. +</p> + +<sect id="sect:dfsg-compliant-gui">How can I make a DFSG compliant Java GUI program? + +<p>Many Java programs use the Swing library for GUI development. For this there +is the <package>libswing-java</package>. Most programs will compile against this library, +but that does not garantee it to work. Not always are all classes implemented or +implemented well. + +<p>An alternative to the Swing library is the Standard Widget Toolkit (SWT, +<package>libswt-java</package>) which is based on the GTK+ library. + +<p>A third alternative is the use the GUI functionality from either +KDE or Gnome. For KDE, the kdebindings tar.gz does the job (is there a +deb package too?). For Gnome there is the +<package>libgnome0-java</package>. + +<sect1>Do swing-based programs work in Debian? + +<p>Swing does work and can be installed, please note that 1.2 and 1.3 +jvms include swing, otherwise you need to download it for your +particular jvm. See later on <ref id="swing-run"> how to make it work. + +<sect>Making Debian packages for Java progams. +<p> + +<sect1>Can the package go into main? + +<p>Yes, <em>but only if</em> it can be build and run with Java programs/tools +in main, and if it has a Debian compliant open source license. +If it needs programs from contrib or non-free, then is <em>must</em> +go into contrib or non-free, depending on the license of the program itself. + +<p>More specifically, if the program can be build and run with +<package>free-java-sdk</package>, then it only depends on Debian packages +from main. The <package>free-java-sdk</package> description states: +"Just install this package, set JAVA_HOME to /usr/lib/fjsdk and try to rebuild +your Java packages. If it works - a package from contrib section can be moved +to main." + +<sect1>What virtual packages could I use? +<p> +<list> +<item><package>java-common</package>. It is the Mother Of All Java +Packages, in the proposed policy. It contains the text of the Policy +(Docbook), as well as utilities +scripts (for instance to build a CLASSPATH from a list of jars +(submissions welcome). +<item><package>java-virtual-machine</package> +<item><package>java-compiler</package> +<item><package>java-compiler-dummy</package>.It is a small tool useful for the transition to the new Policy. Until all +compilers comply with the Policy, java-compiler-dummy provides the following +services: +<list> +<item>Provides: java-compiler so upper packages are happy, +<item>set CLASSPATH before calling the real compiler. +</list> +<item><package>java-virtual-machine-dummy</package>.It is a small tool +useful for the transition to the new Policy. Until all virtual machines +comply with the Policy, java-virtual-machine-dummy provides the following +services: +<list> +<item>Provides: java-virtual-machine so upper packages are happy, +<item>set CLASSPATH before calling the real VM. +</list> + +</list> + +<sect1>Is there a good example Debian package? + +<p>There are many Debian packages of both Java applications and libraries. +These may serve as an good starting point, as it can serve as an example +for making a new Debian package. + +<p>A good start would be to check out the pkg-java project on +Alioth: <url id="http://pkg-java.alioth.debian.org/">. + +<p>Note that there are many ways to make a Debian package, making use +of Ant or Makefiles does not really matter. +But, some tips for good practice are given on the pkg-java page: +<url id="http://pkg-java.alioth.debian.org/developers.html#rules"> and +<url id="http://pkg-java.alioth.debian.org/building.html">. + + +<sect1>What tools are available to make maintaining a Java packages easier? + +<p>At this moment, there is dh_javadoc, which is a tool +in the <package>gjdoc</package> package in Debian unstable. And, there +are tools in <package>cdbs</package> which can help build packages with +<package>ant</package>. + +<chapt>Java Compilers +<p> +<sect>What Java compilers are available in Debian? +<p> +<list> + +<item><package>jikes</package>. Reported to work fine with all JDKs +(1.1 to 1.3), it is suggested you use -E when compiling under +<prgn>Emacs</prgn>. + +<item><package>gcj</package>. Compiles Java source to native code, +also source to bytecode, or bytecode to native code. + +<item><prgn>kjc</prgn> is included in <package>kaffe</package> 1.0.5 and above. +There is no separate package. + +</list> + +<p>The following Java compilers where available in the past, but are no longer +available: + +<list> + +<item><package>guavac</package>. The compiler of Effective Edge +Technologies. This compiler is orphaned upstream; for real work use +gcj or jikes. + +<item><package>tya</package>. A just-in-time compiler, used to compile +Java to byte code. + +<item><package>bock</package>. Java to C compiler. + +<item><package>gck</package>. + +</list> + +<chapt>Java Virtual Machines (JVM) +<p> +<sect>What jvms work in Debian? + +<p>Currently Blackdown's, Sun's and Ibm's jvms work in Debian. (But, +for simple programs such as the ones used for teaching, the free kaffe +VM may be enough. Another solution is to use gcj and to compile to +native code, thus solving the VM problem.) + +<P>All of them can be unpacked in /usr/local with links made in +/usr/local/bin. This will work in any Debian setting and version, the +only issue being is wether or not the version is glibc based or +libc5-based regarding (older versions of Debian do not have glibc +support since it was included in Debian 2.1 codename <em/slink/) + +<sect>What free JVMs are available in Debian? + +<p>The following lists JVMs available in the latest Debian release (4.0, +'etch'): + +<list> +<item><package>kaffe</package> +<item><package>sablevm</package>. +<item><package>gij-4.1</package> +</list> + +<p>If you want to look for available JVMs in a different release, this list can +be reproduced with the command: + +<example> +grep-available -F Provides -sPackage java-virtual-machine +</example>. + + +<sect>What API do these JVMs provide? + +<p>Note that providing an API does not mean that everything is +implemented, and certainly not implemented correctly. But even Sun's +SDK, each out of four confirmed bugs don't get fixed, so don't +disregard free implementation on buggyness or limited implementation +alone. + +<p>Several APIs are compared for GNU Classpath, GNU gcj, Kaffe and Wonka with +<url name="japitools" id="http://rainbow.netreach.net/~sballard/japi/">. + +<sect>Are there known problems? + +<p>Yes, there are. Some of these are reported as Debian bugs. You can +look up the bugs for a specific Debian package at the <url +id="http://www.debian.org/Bugs/" name="Debian Bug Track System">. As +a quick link, here are some packages: + +<list> +<item><url id="http://bugs.debian.org/kaffe" name="kaffe"> +<item><url id="http://bugs.debian.org/gcj" name="gcj"> +<item><url id="http://bugs.debian.org/sablevm" name="sablevm"> +</list> + +<p>As common within the Debian project, the developers would +appreciate good bug reports on found problems. These include the good +description of the problem, the command that gives the problem, the +errors given when running the command, and any other information that +might be relevant. A good tool to report bugs is +<package>reportbug</package>. + +<sect>Do I need a JVM to run a Java program in Debian? +<p> +No, you can try to run the applications without a jvm by compiling +the source code to native code is. + +<sect1>How do I compile to native code? + +<p>You might be able to use <prgn>gcj</prgn> or <prgn>jikes</prgn> (both free +programs), to compile the program. +And use <prgn>gcj</prgn> to convert bytecode to native code. The entire +software chain is free. + + +<sect1>Are there any successes using this approach? +<p>Most certainly, read in <url +id="http://lists.debian.org/debian-java/1999/debian-java-199911/msg00044.html"> +how this was done for the XML parser <prgn>xp</prgn>. +<example> +ezili:~/infosystems/XML/Java> gcj --main=UnTag UnTag.java UnTagHandler.java +/usr/share/java/repository/org/xml/sax/helpers/*.class +/usr/share/java/repository/org/xml/sax/*.class /usr/share/java/repository/com/j +clark/xml/sax/*.class /usr/share/java/repository/com/jclark/xml/parse/*.class +/usr/share/java/repository/com/jclark/xml/tok/*.class +/usr/share/java/repository/com/jclark/util/*.class +/usr/share/java/repository/com/jclark/xml/parse/base/*.class +</example> + +<sect1>Are there any problems with this approach? +<p> +Yes there are also some problems. +<p><prgn>gcj</prgn> does not fully support JNI. Tom Tromey is +responsible for the JNI implementation. As of april 2000 +it is missing one feature (you can't currently compile a +.class file that uses JNI functions to implement its native methods), +but Tom is working on this and hope to have it completed "soon". + +<p>Lack of JNI affects use of Classpath (e.g. as an alternative to libgcj) +as well as small, standalone apps that replace AWT with some really simple +GUI (like using curses, e.g. for small installers). It also affects projects +which have native code for performance reasons. At the moment, gcj basically +forces a CNI port. The only alternative we are aware of is TowerJ, which is +good for commercial projects, but does not offer anything to free software. + +<sect1>Does these work for architectures different than i386? +<p>Possibly not, since libgcj does not build on sparc and no one has +tried this for arm. + +<chapt id="browser-java">Java Plugins for Browsers + +<p>The following section describes how you can use Java in +web browsers in order to be able to run <tt>applets</tt> published +in web servers. + +<sect>Can I use any JVM as a Java Plugin? + +<p>That is a tricky question. My answer would be: "No, but it doesn't +hurt trying" (and don't forget to forward us your findings so we +can update this document) + +<sect id="konqueror-java">Can I use Java in Konqueror? + +<p>Yes, in Konqueror 3.1.1, you Settings->Configure Konqueror. The opened +Control Module has a Java&JavaScript section where you can enter the location of +your JVM. The configuration should look like this: + +<list> + <item>Selected "Enable Java globally" + <item>Selected "Show Java console" + <item>"Path to Java executable" has /usr/bin/java +</list> + +<p>As it says <file>/usr/bin/java</file> it relies on the <prgn>update-alternatives</prgn> +mechanism to point to a JVM that can serve as a plugin. +If you have Sun's J2RE installed, "Path to Java" might also say something like +<file>/usr/local/lib/j2sdk1.4.2/jre/bin/java</file> + +<sect id="netscape-java">Can I use Java in Netscape 6.x/7.x? + +<p>Yes. Make a symbolic link in the <file>/path/to/netscape/plugins</file> +directory to the Java Plugin as can be found in Sun's J2RE: +<example> +/usr/local/netscape/plugins $ ls -la +total 960 +drwxr-sr-x 2 root staff 4096 Apr 30 09:46 . +drwxr-sr-x 9 root staff 4096 Apr 8 20:26 .. +-rw-r--r-- 1 root staff 2363 Feb 8 07:47 ShockwaveFlash.class +-rw-r--r-- 1 root staff 946108 Feb 8 07:47 libflashplayer.so +lrwxrwxrwx 1 root staff 64 Apr 30 09:46 libjavaplugin_oji.so -> /usr/local/lib/j2sdk1.4.2/jre/plugin/i386/ns610-gcc32/libjavaplugin_oji.so +-rwxr-xr-x 1 root staff 19396 Feb 8 07:47 libnullplugin.so +</example> + +<p>If you have Blackdown's J2RE installed the link has to be made to +<file>/usr/lib/j2se/1.4/jre/plugin/i386/mozilla/javaplugin_oji.so</file>. Other +possible locations include <file>/usr/java/j2re1.4.2_04/plugin/i386/ns610-gcc32/libjavaplugin_oji.so</file>, you will need to locate this plugin depending on your +installation. + +<sect>Can I use Java in Mozilla? + +<p>Yes, the mechanism is identical to that of Netscape. However, the plugin +directory in this case is <file>/usr/lib/mozilla/plugins</file>. There is +additional information on how to install Java in Mozilla at the +<url id="http://plugindoc.mozdev.org/faqs/java.html" name="Java FAQ at Mozilla"> + +<P>There might be some issues depending on your version. Mozilla 1.4 +and later (as well as Mozilla Firebox) is compiled with gcc 3.x and +needs a compatible version of the plugin, as provided by JRE 1.4.2 or +later. If you find issues you will need to debug yourself. A common +problem is that the library might not be binary compatible if it was +compiled with a different <prgn>gcc</prgn> version. Some gory details +on how to debug this are described below (contributed by Tim Freeman +and included in the <url +id="http://www.linuks.mine.nu/debian-faq-wiki/MiscellaneousPage" +name="#debian faq wiki">) + +<p>The first problem is that in version 1.6-5 of the +<package>mozilla-browser</package> package, at least, +<file>/usr/bin/mozilla</file> is a shell script that redirects errors +to <file>/dev/null</file>. This is described in <url +id="http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=178721" name="bug +178271"> + +<p>To deal with this, make a copy of <file>/usr/bin/mozilla</file> and +edit out the redirects of file descriptor 2 to /dev/null and run the +copy. You may see something like this on Mozilla's standard error +when it starts: + +<example> +LoadPlugin: failed to initialize shared library /usr/lib/j2se/1.3/jre/plugin/i386/mozilla/javaplugin_oji.so [/usr/lib/j2se/1.3/jre/plugin/i386/mozilla/javaplugin_oji.so: undefined symbol: __vt_17nsGetServiceByCID] +</example> + +<P>This symptom indicates that your Java was compiled with an old +version of GCC, but your Mozilla was compiled with a newer version +(post gcc 3.0.3), and the two are binary incompatible. This is the +case for version 1.3.1.02b-2 of the <package>j2re1.3</package> package +from <url id="ftp://ftp.tux.org">, at least. + +<P>If you're confronted with this symptom, the fix is to get a Java +runtime that was compiled with a more recent gcc. There are several +available; one is <url +id="ftp://ftp.tux.org/pub/java/JDK-1.4.2/i386/01/j2re-1.4.2-01-linux-i586.bin">. +Install that and change the libjavaplugin_oji.so link to point into +the newly installed Java runtime. <P>If you wish to confirm the +diagnosis before attempting the above treatment, you can do it as +follows. Confirm that your Java was compiled with the old gcc by +giving the command: + +<example> + c++filt -s gnu __vt_17nsGetServiceByCID +</example> + +<P>and getting the result: +<example> + nsGetServiceByCID virtual table +</example> + +<p>To confirm that your mozilla was compiled with the new gcc, you can +find its version of the symbol by giving the command: + +<example> + objdump -R /usr/lib/libxpcom.so | grep nsGetServiceByCID +</example> + +<p>and you'll see a line like: + +<example> + 000ec114 R_386_GLOB_DAT _ZTV17nsGetServiceByCID +</example> + +<p>Then you demangle that with the command: + +<example> + c++filt -s gnu-v3 _ZTV17nsGetServiceByCID +</example> + +<P>and get this eminently reasonable output: +<example> + vtable for nsGetServiceByCID +</example> + +<P>The important thing is that the two calls to c++filt both succeeded +but they were told to use different demangling rules, "gnu" for the +first and "gnu-v3" for the second. If this all checks out, then you +should fetch a newer Java runtime as described above. + +<chapt>Java Servlets +<p> +<sect>How can I make Java servlets work? +<p>You can use: +<list> + <item><package>gnujsp</package> + <item>Apache <package>jserv</package>. <url id="http://java.apache.org/jserv/index.html">. + <item>Apache <package>tomcat</package> from <url id="http://jakarta.apache.org/tomcat/">. +</list> + +<p>Also others not yet packaged for Debian but which migh be soon included are: + +<list> +<item>jigsaw from <url id="http://www.w3.org/Jigsaw/">. +<item>Jetty <url id="http://mortbay.com/software/Jetty.html"> (tested +successfully on a potato machine) + +</list> + + +<sect>Do servlets work with kaffe? + +<p>The <file>servlet.jar</file> in Kaffe will not work. It is only a +shell. There is another LGPL implementation that was written by Paul +and Mark Wielaard. It is available at <url +id="http://www.euronet.nl/~pauls/java/servlet"> these will have (have +been?) added Apache JServ package so the user doesn't have to +download Sun's classes any longer. + +<sect>Do I need non-free Java in order to run servlets? +<P>Not known. Possibly not, need to explain. + +<chapt>Java Policy +<p> +<sect>Is there a Java policy for Debian? +<p> +It is still in the works. The current policy addresses <em>some</em> +of the problems. It has not been officially released. You can find +it at <url id="http://www.debian.org/doc/packaging-manuals/java-policy/">. +The Java Policy can also be found in the <package>java-common</package> +package. You might want to also take a look at the +<url id="http://wiki.debian.org/DebianJavaPackaging" +name="Common Java Packaging"> entry in the Debian wiki. + +<sect>Are there holes in the Java Policy? +<p>Yes, some until under discussion. Please check out the +<url id="http://bugs.debian.org/java-common" name="bugs against +the java-common package">. Thus it is <em>very</em> inconvenient to +use several compilers of virtual machines since there is not one +CLASSPATH setting for all of them. + +<chapt>Other Java alternatives for Debian +<p>If the Java packages provided in Debian are not sufficient for your +needs you might need to take a look at other alternatives. Please understand +that these alternatives are not supported by the Debian project directly, +you might get help, however, from the debian-java mailing list if you +encounter issues with them. + +<P>Some of the alternatives presented use Debian packages which is +convenient, since the user/administrator does not need to care on installation +issues. However, mixing packages that come from a source which is not +the Debian project might cause conflicts with your installation some times. +Of course, Debian tries to integrate as many free software efforts as +possible, so some of the alternatives described below might (if license +permits) be included in Debian in the near future. + +<sect id="blackdown-pack">How can I get Debian packages from Blackdown? + +<p>If the releases provided aren't recent enough +for you, you can of course install the files from +the Blackdown mirrors. You can either use the Debian packages +provided by Blackdown or download their tar files. + +<p>(contributed by Federico Mennite) If you want to use their packages, add +the following line +<footnote> +Use only one of them, it could be <em>potato</em>, <em>woody</em>, +<em>testing</em> (<em>sarge</em>) or (<em>unstable</em>) (<em>sid</em>) depending +on the Debian release you are running, or it could be +<em>testing</em> or <em>unstable</em> if you are running development +releases. +</footnote> +to your <file>/etc/apt/sources.list</file>: + +<example> +deb proto://url/debian potato main non-free +deb proto://url/debian woody main non-free +deb proto://url/debian testing main non-free +deb proto://url/debian unstable main non-free +</example> + +<p>Where <em>proto://url</em> is one of the mirrors from the list +available at +<url id="http://www.blackdown.org/java-linux/java-linux-d2.html">. +<!-- Previously at: +url id="http://www.blackdown.org/java-linux/mirrors.html" +--> +<footnote> +You need the <em>main</em> archive too since now there is a +<package>j2se-common</package> package which resides there. +If you had already installed j2sdk when the +above dependency did not exist you would get warnings once +you do an <prgn>apt-get update</prgn> or <prgn>apt-get upgrade</prgn>. +</footnote> +For example, in Debian 3.0 using the main site (in the US) you would use: +<example> +deb ftp://ftp.tux.org/pub/java/debian unstable non-free +</example> + +<p>And then do: + +<example> +$ apt-get update +$ apt-get install j2sdk1.4 +</example> + +<P>The packages will download all the library files into +<file>/usr/lib/j2se/</file>, you just need to configure your +system to use that jvm. If you use these Debian packages you will +not need, for example, to configure your web browser: the symbolic +links described in <ref id="netscape-java"> for +<file>libjavaplugin_oji.so</file> will be created, as well as the +alternative location of <file>/usr/bin/java</file> pointing to the +j2se's Java. + +<P>Note that, at the moment of this writting, there are only Blackdown +packages for <em>unstable</em> and <em>testing</em> of Java 1.4. + +<p>(contributed by Paul Reavis) If you download and install the +JDK tar.gz files, unpack them into <file>/usr/local/jdk1.1.x</file>, and +use symlinks to create a <file>/usr/local/jdk</file> and +link in binaries to <file>/usr/local/bin</file> or whatever. It is not at all +difficult to install these. However, you can get segfaults under some +conditions depending on your libraries. + +<p>Here is a list of releases that are known to work under each Debian +release, and what other software needed, if any, to make it happen. + +<list> +<item>rex/bo: 1.1.5v7 (libc5). +<item>hamm:1.1.5v7 (glibc), also needed latest glibc from <em/slink/. +<item>slink: 1.1.6-test2 (glibc). +</list> + +<sect1 id="swing-run">Making swing work in Debian + + +<p>(from Paul Reavis) [A quickie on getting Swing working under Debian +or any Linux really] + +<p>Yes, it does work with the linux JDK; Swing is 100% Pure Java +(tm)(c)(SFD) and therefore should run under any compliant JVM. Paul +Reavis reported converting a commercial app (350+ classes) over to a +fully-Swing GUI; I've had no problems so far. + +<p>If you are using jdk 1.1.3 or below, all you need are the class +files. So, the easiest thing to do is grab the solaris distribution, +in tar.Z format, from javasoft. Depending on phase of moon, they +either call it swing or JFC 1.1 (to distinguish from 1.2, which is +part of Java 1.2). The current version is Swing 1.0.2 (not to be +confused with Java 1.0.2!). If you are using jdk 1.2.2 do not download +Swing (it is already integrated in the jdk). + +<p>I don't have the archive handy here, so we'll pretend it's named +swing.tar.Z. It is recommended you install it in /usr/local. So + +<example> + skronk# cd /usr/local + skronk# tar xzf /tmp/swing.tar.Z +</example> + +<p>Now you should have a /usr/local/swing directory. To test, make +sure your JAVA_HOME variable is set, and CLASSPATH is unset, and run +the "runnit" script in each example. To be painfully obvious, do this: + +<example> + skronk$ cd /usr/local/swing/examples/SwingSet + skronk$ echo $JAVA_HOME + /usr/local/jdk + skronk$ unset CLASSPATH + skronk$ echo $CLASSPATH + + skronk$ ./runnit +</example> + +<p>Of course, your directories, shell prompt, and mileage will vary. +To use with your own applications, just add the jars you want to your +classpath. + +<sect1>Making Java 2 work in Debian +<p> +If you wish to use Sun's or Blackdown's jdk 1.2 or later in Debian download the +packages provided by Blackdown (they are available in aptable +directories) from the different mirrors available in +<url id="http://www.blackdown.org/java-linux/mirrors.html"> (check the debian +subdir). Currently there are i386 packages for the Java2 SDK and RE, JAI, +Java3D and JMF. This is the recommended mechanism for more information +read <ref id="blackdown-pack">. + +<P><em>Or</em> you can download the archives yourself (that is, the tar.gz, +no the .deb package) and use the following mechanism: + +<list> +<item>Make a directory under <file>/usr/local</file> + (for example <file>/usr/local/sun</file>). +<item> Download the archine into this directory, then unpack it. A + directory jdk1.X + <footnote><em>X</em> will depend on the Java 2 version you are downloading, + it can bee 1.2.1, 1.2.2, 1.3 or even 1.4</footnote> + will be created. +<item> Adjust the alternatives to work correctly: +<example> + update-alternatives --install /usr/bin/javac javac /usr/local/sun/jdk1.X/bin/javac 120 + update-alternatives --install /usr/bin/java Java /usr/local/sun/jdk1.X/bin/java 120 +</example> +<item> Check your alternatives with "type" +<example> + type javac + type java +</example> +</list> + +<p>You should have now a fully working jdk 1.X environment, virtual machine +and compiler included. + +<p>You might need to change your <file>/etc/profile</file> adding the proper +definitions of some environment variables (<tt>CLASSPATH</tt>, +<tt>JAVA_COMPILER</tt> and <tt>JAVA_HOME</tt>) so that Java programs +can find the kit you just have installed. The following example show +which settings you could add if you had installed Sun's 1.2.2 jdk: + +<example> +# JDK 1.2.2 (.tar) +export CLASSPATH=.:/usr/local/sun/jdk1.2.2/lib:/usr/local/sun/jdk1.2.2/jre/lib +export JAVA_COMPILER=javacomp +export JAVA_HOME=/usr/local/sun/jdk1.2.2 +export PATH=$PATH:/usr/local/sun/jdk1.2.2/bin +</example> + +<p>Note: As Juergen Kreileder correctly pointed me out + The preferred name for versions >= 1.2 is Java 2 SE (Standard Edition). + The jdk1.3 now is called "Java2 SDK v1.3" or "J2SDK 1.3". The jre1.3 + now is called "Java2 RE v1.3" or "J2RE 1.3". + +<sect>How can I integrate Sun's J2SE SDK with Debian 3.1? + +<p>Warren Dodge explains how this can be done for Debian testing: +the first step is to download the J2SE SDK components +from <url id="http://java.sun.com/j2se/downloads.html"> into, +e.g. <file>/var/install/java/1.4.2</file>. Make sure that you have write permission to +the directory, and make the installer executable. Running the installer +<prgn>./j2sdk-1_4_2_02-linux-i586.bin</prgn> will create a directory +<file>j2sdk1_4_2_02</file> which can be moved to <file>/usr/local/lib</file>. +Next, create a link +<tt>ln -s /usr/local/lib/j2sdk1_4_2_02 /usr/local/lib/jdk</tt> which allows you +to use the latter location to refer to the Java environment and makes upgrading +a lot easier in the future. + +<p>Because Debian does not have an installer packages for Sun's J2SE, a dummy package +needs to be made to let Debian know that a J2SE is installed. This is done as follows. +Use the 'dummy' package control files provided by <package>java-common</package> to +satisfy dependencies: +<example> +mkdir -p /var/install/java/pkg +cd /var/install/java/pkg +cp /usr/share/doc/java-common/dummy-packages/*.control . +equivs-build java-compiler-dummy.control +equivs-build java-virtual-machine-dummy.control +equivs-build java1-runtime-dummy.control +equivs-build java2-compiler-dummy.control +equivs-build java2-runtime-dummy.control +</example> +<p>You should now have five packages in /var/install/java/pkg which should be installed. + +<p>The command <prgn>update-alternatives</prgn> is used in Debian to choose which of +several pacakges to use when several can do the same thing. ("Java" can also be provided +by kaffe, Blackdown (see above), etc). See "man update-alternatives" for more details. +Use this command to install the programs you need with commands like: +<example> +update-alternatives --verbose --install /usr/bin/java java /usr/local/lib/jdk/bin/java 500 \ + --slave /usr/share/man/man1/java.1 java.1 /usr/local/lib/jdk/man/man1/java.1 +</example> + +<p>Run java once as root to allow system preference directories to be created and to check +if Sun's <prgn>java</prgn> is working properly: +<example> + java -version +</example> + +<sect>How can I integrate Sun's J2SE SDK with Debian 3.0? + +<p> The procedure is similar to the one described for Debian 3.1 . However, +the java-common in stable does not have the *.control files. + Therefore, you need to install the + java-common package from testing or unstable. Versions 0.19 and 0.20 can be safely + be installed and require the installation of the equivs package, but the one + from stable is just fine. + +<p>Notice, however, that newer J2SE versions (notably 1.4.2_04 instead of +1.4.1_02) might depend on newer libc6 or libgcc1 libraries. If you cannot +backport (recompile) this package to your libraries you will need are limited +to using jdk 1.3.1-11 (which requires libstdc++2.9-glibc2.1 from the +<em>oldlibs</em> section). + +<sect>Java programs not yet available on Debian +<p> +The following are programs that have not yet been packaged for Debian +nor is there an installer. There are quite a lot Java programs out +there and this list is not an exhaustive list, it only includes +programs that <em>might</em> be packaged for Debian or those that +someone is working on an installer for: +<list> +<item>BlueJ. A development environment for Java with editor, compiler, +virtual machine and debugger. See <url +id="http://bluej.monash.edu.au/"> +<item>Jacob (Java Commando Base): project maintainer and visualiser +for Java in Emacs. See <url +id="http://home.pages.de/~kclee/clemens/jacob">. + +<item>Emacs in Java. See <url id="http://jemacs.sourceforge.net/">. + +<item>Netbeans developer, now called <em>Forte</em>. Based on the +Javabeans architecture. See <url id="http://www.netbeans.com">.Sun +recently announced they would open-source it. See <url +id="http://www.sun.com/forte/tools4dotcom/opensource.html">. + +<item>AnyJ. Graphic environment to develop applications, applets and +servlets. More info in <url id="http://www.netcomputing.de">. + +<item>Free Builder. A Java IDE written in Java and distributed under +the GPL <url id="http://www.freebuilder.org">. + +</list> + +<appendix>Older Debian GNU/Linux versions + +<p>This appendix is included for historical reasons. It contains +information that used to be in the FAQ (and indeed still is ;), but +that only has historical value. + +<sect>Debian 2.2 'potato' +<p> +<list> + +<item>Libraries +<list> +<item>lib-fop-java +<item>lib-gnu.getopt-java +<item>lib-gnu.regexp-java +<item>lib-openxml-java +<item>lib-rxtx-java +<item>lib-sax-java +<item>lib-xp-java +<item>lib-xslp-java +<item>lib-xt-java +<item>lib-dom-java +<item>libpgjava +<item>libgcj0 +</list> + +<item><package>bock</package> Bootstrap-only compiler kit for a subset of Java(tm) + +<item><package>doc++</package>. A documentation system for C/C++ and Java + +<item><package>fastjar</package> a complete replacement for the jar +utility written in C under the GPL <url +id="http://www.engr.orst.edu/~burnsbr/fastjar/"> (check <url +id="http://lists.debian.org/debian-java/1999/debian-java-199908/msg00015.html">. + +<item><package>java2html</package>. Highlits Java sources for WWW presentations. + +<item><package>gcj</package> The GNU compiler for Java(TM). + +<item><package>global</package>.Source code search and browse. + +<item><package>guavac</package>. A Java compiler. + +<item><package>jikes</package>. Fast Java compiler adhering to +language and VM specifications + +<item><package>jikes-pg</package>.Jikes Parser Generator. + +<item><package>oo-browser</package>.Object Oriented (X)Emacs Class Browser. + +<item><package>mmake</package>.Makefile generator for Java programs. + +<item><package>cocoon</package>. A XML/XSL publishing framework servlet + +<item><package>bsh</package> A Java scripting environment. +<item><package>cup</package>. LALR parser generator for Java. +<item><package>freetds-jdbc</package>. Pure Java JDBC driver for MS +SQL and Sybase. + +<item><package>gnujsp</package>. +A free implementation of Sun's Java Server Pages (JSP 1.0) + +<item><package>jlex</package>.A Lex-style lexical analyser generator +for Java + +<item><package>jserv</package>Java Servlet 2.0 engine with an optional +Apache module + +<item><package>tya</package>.JIT-compiler for Java. + +<item><package>ibm-jdk1.1-installer</package>. Installer for IBM +Developer Kit for Linux, Java(TM) Technology Edition. + +<item><package>jdk1.1</package>.JDK 1.1.x (Java Development Kit) - +Runtime only + +<item><package>jdk1.1-dev</package> JDK 1.1.x (Java Development Kit) + +<item><package> biss-awt</package> a Java GUI application programming +framework. + +<item><package>jdk1.1-native</package>.JDK 1.1.x Runtime - native +threads extensions + +<item><package>jdk1.1-native-dev</package>. JDK 1.1.x - native +threads extensions. + +<item><package>vrwave</package>.VRML 2.0 java-based browser + +</list> + +<p>Also many editors (jed, elvis, vim, emacs, fte, xcoral,zed ....) have +support for Java syntax. + +<sect>Debian 2.1 'slink' +<p> +<list> +<item><package>jdk 1.1.5v5</package> +<item><package>vrwave</package>. A Java VRML browser. +<item><package>icq-java</package>. An installer +for the ICQJava program. +<item><package>jde</package>. A Java Development +Enviroment for Emacs <url id="http://sunsite.auc.dk/jde">. +<item><package>jlex</package>. A lexical analyser generator similar to the UNIX <prgn>lex</prgn>. +<item><package>mmake</package>. A generator of Makefiles for java +programs. More info at <url id="http://www.tildeslash.com/mmake"> +<item><package>libpgjava</package>. A Java class that +enables communication with the PostgreSQL database using JDBC. +<item><package>cup</package>. A parser similar to +<prgn>yacc</prgn>. +<item><package>ilu-javadev</package>. Development +header and libraries for the Inter-Language Unification System. +</list> + + +<sect1>I've installed the latest jde package...what I have to do to let Emacs enter jde-mode automatically when loading a Java source file? +<p>As explained in <file>/usr/doc/jde/README.Debian</file>, all that +is required is putting +<example> + (require 'jde) +</example> +into your <file>~/.emacs</file> file. +<p>Note that other add-on packages to Emacs are not enabled by default +either, e.g., AucTeX. + +<sect>Debian 2.0 'hamm' +<p> +<list> +<item><package>jdk 1.1.5v5</package> +</list> + +<sect>Debian 1.3.1 'bo' +<p> +<list> +<item><package>jdk 1.0.2</package> +</list> + +</book> |