path: root/debian-java-faq.sgml

<!doctype debiandoc system>

<book>

<titlepag>
<title>Debian Java FAQ.</title>
<author>
<name>Javier Fernández-Sanguino Peña </name>
<email>jfs@computer.org</email>
</author>
<version><date>

<abstract>
Answers to Frequently Asked Questions on Debian
and Java. Any changes to this FAQ are appreciated, please send them to the
current maintainer. 
</abstract>

<copyright>
<copyrightsummary>Copyright &copy; 1998,1999 Javier Fernández-Sanguino
Peña, The current FAQ has been made with tidbits of information from
the debian-java mailing list and made available freely to all interested.</copyrightsummary>

</titlepag>


<toc>


<chapt>Introduction
<p>

<sect>Introduction to this FAQ
<P>This FAQ was started by Javier Fernández-Sanguino who on
Feb 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 responsability" 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 kind of
question 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.

<sect>What is java?
<p>
Java is a strongly-typed platform-independant object-oriented programming
language often associated with the World Wide Web. Java was developed by 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-independant 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.
 
A common API, shipped with all commercial 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.
 
The multithreading support can happen either in kernel threads or user
threads, depending on the implementation of the java virtual machine used. 
<sect>Why would I be interested in Java?
<p>
TODO 

<sect>What is a JIT?  
<p>
Acronym for Just In Time, 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. However good places for Java and Linux could be:


<list>
<item>Enterprise in a Nutshell by  Gary Meyer, at <url id="
http://www.linuxdoc.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 Linux Journal Magazine, the following articles might be
worth reading:
<list>
<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">.

<item>Issue 45 <url
id="http://www.linuxdoc.org/LDP/LG/issue45/gibbs/Linux_java.html">
<item>Issue 33 <url id="http://www.linuxdoc.org/LDP/LG/issue33/burtch.html">
<item>Issue 32 <url id="http://www.linuxdoc.org/LDP/LG/issue32/rojansky.html">
<item>Issue 25 <url id="http://www.linuxdoc.org/LDP/LG/issue29/hamilton.html">
</list>


<item>Linux users worlwide includes information on how to use Java an
Linux <url id="http://linuxusers.webprovider.com">.

<item>Linux Java Tips and Hints at <url
id="http://www.parnasse.com/java.shtml">.



<item>The Java and Linux Page <url id="http://www.geocities.com/SiliconValley/Platform/8187/java/Linux_java.html">

<item>The Java-CGI HOWTO from David H. Silber. <url
id="http://www.linuxdoc.org/HOWTO/Java-CGI-HOWTO.html">. Explains how
to set up your server to run Java CGIs. Maybe it is worth looking at
servlets.

</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 try starting with <url
id="http://members.tripod.com/~mpTOOLS/ring.html" name="Open-Source Java">
, if you are looking for applets with source code look at <url
id="http://javaboutique.internet.com/javasource.html">. Check also
<ref id="free">


<sect>Status of Java in Debian
<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 these tools are not available in the standard Debian
distribution for licensing reasons as opposed to some technical
motivation.

<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://www.debian.org/Lists-Archives/debian-java-9912/msg00015.html"> and
<url id="http://www.debian.org/Lists-Archives/debian-java-9910/msg00017.html">. This
section is a summary of the information therein.

<sect1>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.


<sect1>Java1 JVM/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 "pin compatible"
  with Sun's implementation in all cases so there may be
  interoperation issues in some casses. Kaffe comes with a big class library.
<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.

<sect1>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
  is still performant and becoming more so and it is believed IBM's Jikes 
  compiler understands Java2 concepts such as weak references.

<sect1>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 I know, has not been cloned.

<sect1>Debugger (jdb equivalent)
<p>Debian has no debugger currently.

<p>Gdb can debug 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.

<sect2>What free edit-interactive/graphical debugging tools are available on
Debian?
<p>jde, ddd, more?
<sect2>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.
                                             

<sect1>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>

<sect1>Jar tool
<p><package>FastJar</package> which is indeed very fast.

<sect1>Javadoc tool
<p><package>doc++</package> can work with C++ and Java.

<sect1>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).

<sect1>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.

<sect1>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. 


<chapt>Java development
<p>
<sect>What java development platforms are available in Debian?
<p>
<list>
<item>Sun's jdk 1.1 (port made by Blackdown <url id="www.blackdown.org">)
<item><prgn>kaffe</prgn>.
<item>ibm's jdk (see <ref id="installer">)
</list>

<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"> or <url id="http://www.transvirtual.com">.

<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>There is a list on free java at <url id="http://www.lists.deus.net/mailman/listinfo/free-java">, also look <url id="http://www.gnu.org/software/java/"> for information about Free Java.

<sect>Questions on commercial platforms  and license concerns

<sect1>JDK1.2
<p>
<sect2>Why is Sun's 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".

<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. 

<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 Japhar/Classpath project) have decided to
  challenge Sun's legal position and are going ahead with Java2.


<sect1 id="ibm-jdk1.1">IBM's jdk1.1
<P>
<sect2>Can Debian distribute IBM's jdk1.1?
<p>
It seems not. It has the following license:
<example>
Program Code

Consists of the IBM Developer Kit for Linux(R), Java(TM) Technology Edition,
Version 1.1.8, in Binary Code form, as modified by IBM to run on the RedHat(R)
6.0 Linux or Caldera(R) OpenLinux 2.2 Operating systems. The Program Code
consists of the Java virtual machine, the Java platform core classes and
supporting files (also known as the Java Runtime Environment or JRE) Java Tool
Kit, Documentation and Java Samples. Program Code may include soft copy
documentation, readme files, program data and such like.


You may only use the Program Code if you are a current licensee of Redhat 6.0
Linux or Caldera OpenLinux 2.2 Operating systems and the Program Code may only
be used in conjunction with such products.
</example>
<p>See bug #54641 for an issue about IBM JDK. You can dowload it from
<url id="http://www.ibm.com/java/jdk/118/linux">.

<sect2>Is it possible to obtain a licence for Debian 2.1?
<p>It would still be non-free, because of item 8 in the DFSG "License Must Not Be 
Specific to Debian".

<sect1>JRE
<p>
<sect2>Can Debian distribute JRE?
<p>
(from <url id="http://www.debian.org/Lists-Archives/debian-java-9908/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>
  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>
  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,


<chapt>Java Compilers
<p>
<sect>What Java compilers are available in Debian?
<p>
<list>
<item><package>guavac</package>. The compiler of Effective Edge Technologies. This compiler is orphaned upstream, for real work use gcj or yikes.
<item><package>tya</package>. A just in time compiler, used to compile java to byte code.
<item><package>yikes</package>.
<item><package>bock</package>. Java to C compiler.
<item><package>gcj</package>. Compiles Java source to native code, also source to bytecode, or bytecode to native code.
<item><package>gck</package>. Is this available?
<item><prgn>kjc</prgn> is included in <prgn>kaffe</prgn> 1.0.5. There currently is no separate package.
</list>

<chapt>Java Virtual Machines (JVM)
<p>
<sect>What jvms work in Debian?

<p>Currently  Sun's jdk and Ibm's jdk 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.)


<sect>What free JVMs are available in Debian?
<p>
<list>
<item><package>kaffe</package>. Cannot run all programs, although it is alleged to run Jigsaw (a 10Mb distribution) see <url id="http://www.de.debian.org/Lists-Archives/debian-java-9911/msg00038.html">.
</list>
<sect>Are there known problems?
<p>
<list>
<item>Kaffe loops endlessly on the XML parsing.
</list>

<chapt>Java-related programs
<p>
<sect>What java related programs are available in Debian?
<p>
<sect1>Deban 2.1 'slink'
<p>
<list>
<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>


<sect2>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 /usr/doc/jde/README.Debian, all that is required is
putting
<tt>
 (require 'jde)
</tt>
into your <file>~/.emacs</file> file.
<p>Note that other add-on packages to Emacs are not enabled by default
either, e.g., AucTeX.

<sect1>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://www.debian.org/Lists-Archives/debian-java-9908/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. (see <ref id="installer">).

<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>

Also many editors (jed, elvis, vim, emacs, fte, xcoral,zed ....) have
support for Java syntax.

<sect1>Is there a a free javadoc implementation?  

<p>You might take a look at <url
id="http://www.zib.de/Visual/software/doc++/">, it is package for
Debian, in packages <package>doc++</package> and
<package>doc++-doc</package> (documentation).


<sect>Making packages for Java progams.
<p>

<sect1>Can the package go to main?
<p>
Since there is not yet a free java environment in Debian, the
dependance on any package to JDK avoids any Java program to be in
<file>main</file> even if it uses a free license, the program should
be moved to <file>contrib</file>. <em>But</em> if you can sucessfully
demonstrate that your program can compile and work with free tools it
can be moved to <file>main</file>.

<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>


<sect>Installer packages
<p>
<sect1 id="installer">What Java programs have an installer?
<p>
<list>
<item><prgn>vajava</prgn> is a visual IDE for Java. You can find it in <url id="http://software.ibm.com/ad/vajava">.<em>TODO: check copyright</em>. The installer can be found at <url id="http://www.dat.etsit.upm.es/~jfs/debian/vajava">.

<item><prgn>ibm-jdk1.1</prgn>. Installer for IBM Developer Kit for
Linux, Java(TM) Technology Edition. It will install an alpha version
1.1.6 of the IBM Developer Kit.  The IBM Developer Kit is a
development environment for writing applets and applications that
conform to the Java 1.1 Core API.  Its compiler and other tools are
run from a shell and have no GUI interface.
<p>
The IBM Developer Kit includes the IBM JIT (libjitc.so) which is used by
all tools by default. Look for it in <url id="http://master.debian.org/~doko">. Needs to be upgraded to 1.1.8. However it seems that providing an installer might break their license (see <ref id="ibm-jdk1.1">)

<item><prgn>jdk1.2-installer</prgn>. Look for it in <url
id="http://www.pobox.com/~julio/debian/jdk1.2-installer/">. This one
works for the pre-release version, a little work is needed in order to
install the release candidate version. (Update, April 2000, the link seems
to be broken, anyone has one?)


</list>


<sect1>What Java programs could I develop an installer to?
<p>
<list>
<item><prgn>jdk-1.2.2</prgn> SE  Standard Edition
  <url id="http://www.javasoft.com/products/jdk/1.2/download-linux.html">.

<item>Blackdown's <prgn>jdk-1.2.2</prgn>
<item><prgn>jbuilder3</prgn>. A java IDE from Inprise (written in
java) <url
id="ftp://ftp.inprise.com/pub/jbuilder/jb3foundation/sol_linux/">.
Works well.
 
<item><prgn>netbeans</prgn>. Another java IDE (also written in java) <url id="http://www.netbeans.com/"> for writing bean based GUI apps.  
</list>

<chapt>Java servlets
<p>
<sect>How can I make Java servlets work?
<p>You can use:
<list>
<item>GNUJSP
<item>Apache Jserv. <url id="http://java.apache.org/jserv/index.html">.
</list>
Also others not yet packaged for Debian but which migh be soon included are:
<list>
<item>tomcat from <url id="://jakarta.apache.org/tomcat/">.
<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 commercial 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 in <url id="http://www.debian.org/~bortz/Java/policy.html">.

<sect>Are there Holes in the Java Policy?
<p>Yes, some until under discussion. Thus it is <em>very</em> inconvenient to
use serveral compilers of virtual machines since there is not one
CLASSPATH setting for all.

<chapt>Running Java in Debian
<p>
<sect>Making jdk 1.2 work in Debian
<p>
If you wish to use Sun's or Blackdown's jdk 1.2 in Debian you can use the following mechanism.
<list>
<item>Make a directory under /usr/local (for example /usr/local/sun).
<item> Download  the  archine into  this  directory,  then  unpack it.   A
   directory jdk1.2.2 will be created.
<item> Adjust the alternatives to work correctly:
<example>
   update-alternatives --install /usr/bin/javac javac usr/local/sun/jdk1.2.2/bin/javac 120
   update-alternatives --install /usr/bin/java java usr/local/sun/jdk1.2.2/bin/java 120
</example>
<item> Check your alternatives with "type"
<example>
   type javac
   type java
</example>
</list>

You should have now a fully working jdk 1.2 environment, virtual machine and compiler included.



<sect>Is there a way, using free software, to run a Java program in Debian?
<p>
Yes there is, since the problem currently now is the jvm you can try to run applications without a jvm. How? Compiling to native code is the solution.
<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
sofwtare chain is free.


<sect1>Are there any successes using this approach?
<p>Most certainly, read in <url id="http://www.debian.org/Lists-Archives/debian-java-9911/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.


<sect>Other 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">.
<item>CodeGuide. <url id="http://www.omnicore.com">. Free license for
non-commercial use (CHECK).
</list>.



</book>