Packaging Java with Javatools

   Javatools replaces the existing jarwrapper package and also contains
   programs to help packagers in creating packages for Java programs and
   libraries.

Packaging tools

   The javahelper package consists of several small programs which make
   packaging Java programs and libraries easier. They are generally
   designed to work in the same fashion as the debhelper programs, but
   start with the jh_ prefix.

   All of the programs have their command line arguments documented in
   manpages.

jh_build

   Many Java programs and libraries are distributed without sane build
   systems. jh_build provides a simple interface for building Java source
   code into Jars, including setting the appropriate entries in the
   manifest.

   In almost all cases all that needs to be done to call jh_build is to
   set JAVA_HOME and CLASSPATH and then call jh_build with the name of
   the jar and the directory containing the source.

JAVA_HOME=/usr/lib/jvm/default-java
CLASSPATH=/usr/share/java/esd.jar:/usr/share/java/jsch.jar
jh_build weirdx.jar src


   This command will compile all the Java files under src, set the
   classpath in the manifest and build it all into weirdx.jar.

   A couple of other options are worth mentioning. If this jar contains
   an application rather than a library then the -m or --main option can
   be used to set the Main-Class attribute in the manifest which will
   allow the resulting jar file to be be executed

   jh_build also provides a --clean parameter which should be called in
   the clean target of debian/rules.

jh_libs

   For library packages Debian Java policy currently requires that the
   libraries be installed to /usr/share/java in a versioned format and
   with an unversioned symlink. jh_libs will take a jar and correctly
   install it.

   As with debhelper programs, this can either take a jar as a parameter,
   or read a list of jars from a file in the Debian directory. It also
   follows the -p, -i and -s semantics of debhelper for selecting which
   packages to install the jar to. When operating on a package, jh_libs
   will read the list of library jars from debian/package.jlibs or
   debian/jlibs.

   The jlibs file is a list of jars to install, one per line, and works
   exactly the same as listing them on the command line. Each jar is
   installed to debian/package/usr/share/java/ in the appropriate
   versioned and unversioned forms.

jh_depends

   jh_depends works like dpkg-shlibdeps, but for jar files. For each jar
   in the package it takes the jars on which it depends and finds the
   packages to which they belong. These are included in the debhelper
   substvars as ${java:Depends}. The control file can then just list that
   variable which is filled in automatically.

   This is done by reading the Class-Path attribute from the manifest of
   each jar. Jar files should include this attribute to prevent
   applications which use them from needing a full recursive classpath in
   their startup scripts and to prevent unneccessary transitions when the
   library changes its dependencies. If the package is not built with
   jh_build and the upstream build system doesn't set it correctly then
   jh_manifest can be used to fix this.

   If the application uses executable jars (see Runtime support below)
   then jh_depends will also add the appropriate depends on jarwrapper
   and the correct Java runtime.

jh_manifest

   Many upstream build systems do not set the Class-Path attribute in the
   jars they create. This leads to several unwanted problems, such as
   expanding the classpath which applications have to use and introducing
   unneccessary transitions. They also may not set the Main-Class
   attribute. Both of these are required for running jars with the -jar
   parameter.

   jh_manifest can fix the manifest files of jars. It can either read
   from a manifest file in the Debian directory or run in a mode which
   updates all the jars with the CLASSPATH environment variable.

   The manifest files can either be debian/package.manifest or
   debian/manifest. The format of this file is a list of jars and
   indented below each one a list of manifest elements to set:

usr/share/weirdx/weirdx.jar:
 Main-Class: com.jcraft.weirdx.WeirdX
 Debian-Java-Home: /usr/lib/jvm/default-java


jh_exec

   The Runtime support section below describes running executable jars
   directly. jh_exec will scan package directories for jars in the paths,
   or symlinks to jar from the paths, and ensure that they have been set
   executable if necessary.

jh_makepkg

   jh_makepkg will create template Debian packages for Java programs and
   libraries similar to dh-make. It should be run in the source directory
   and it will create the orig.tar.gz and most of the files in the Debian
   directory, which need only small changes neccessary to build the
   package.

java-propose-classpath

   Some upstreams have complicated classpaths which may not be obvious to
   the packager when using jh_manifest to set the Class-Path attribute.
   java-propose-classpath will unpack a jar and look at the symbols
   imported to the class files, then scan all the jars in
   /usr/share/java. This shouldn't be run in the build since it is slow,
   and there may be ambiguities that the packager must resolve. It is
   still very useful for the packager as most of the time it will get it
   right automatically.

Runtime support

   Javatools also provides some runtime support. Unlike compiled
   programs, or purely interpreted programs with hash-bang lines, Java
   programs cannot be directly executed. Many upstreams expect them to be
   run using java -jar jarname or java classname. This is not generally
   acceptible in systems which expect to just be able to run the command
   or launch it from a menu. As a result, many packagers are writing
   wrapper scripts which just call java with the correct classpath, jar
   and main class.

jarwrapper

   There is an alternative to wrapper scripts, however. The binfmt_misc
   kernel module allows the kernel to call out to a program in userspace
   to execute specific types of file. jarwrapper registers itself as a
   handler for executable jars. This is done by reading values from the
   manifest file.

   In order for executable jars to work the following attributes must or
   may be defined in the manifest. These attributes can be set using
   jh_build and jh_manifest.
     * Main-Class: The name of the class to be run when the application
       starts. (REQUIRED)
     * Class-Path: The path to all the jar files on which this jar
       depends. (REQUIRED unless empty)
     * Debian-Java-Home: A Debian-specific property if this application
       depends on a specific runtime. Specify the path to the runtime
       which should be used. Multiple space-separated paths may
       be given if any of the runtimes will work. (OPTIONAL)
     * Debian-Java-Parameters: A Debian-specific property if this
       application needs extra options to the JVM. (OPTIONAL)

Putting it together

   This section shows the debian packaging generated by jh_makepkg for an
   application and a library using jh_build.

Sample Library Packaging

debian/control

Source: jsch
Section: libs
Priority: optional
Maintainer: Matthew Johnson <mjj29@debian.org>
Build-Depends: debhelper (>= 5), javahelper, default-jdk-builddep, libzlib-java
Standards-Version: 3.7.3
Homepage: http://www.jcraft.com/jsch/

Package: libjsch-java
Architecture: all
Depends: ${java:Depends}, ${misc:Depends}
Description: Java secure channel
 JSch is a pure Java implementation of SSH2. JSch allows you to
 connect to an sshd server and use port forwarding, X11 forwarding,
 file transfer, etc., and you can integrate its functionality
 into your own Java programs. JSch is licensed under a BSD style
 license.


debian/rules

#!/usr/bin/make -f

export JAVA_HOME=/usr/lib/jvm/default-java
export CLASSPATH=/usr/share/java/zlib.jar

build: build-stamp
build-stamp:
        dh_testdir
        jh_build jsch.jar src
        touch $@

clean:
        dh_testdir
        dh_testroot
        jh_build --clean
        dh_clean
        rm -f build-stamp jsch.jar

install: build
        dh_testdir
        dh_testroot
        dh_clean -k
        dh_installdirs

binary-arch: build install
        # Java packages are arch: all, nothing to do here

binary-indep: build install
        # Create the package here
        dh_testdir
        dh_testroot
        dh_clean -k
        dh_install -i
        dh_installdocs -i
        dh_installchangelogs -i
        dh_javadoc -i --sourcedir=src
        jh_libs -i
        jh_depends -i
        dh_compress -i
        dh_fixperms -i
        dh_installdeb -i
        dh_gencontrol -i
        dh_md5sums -i
        dh_builddeb -i

binary: binary-indep binary-arch
.PHONY: build clean binary-indep binary-arch binary install


debian/libjsch-java.jlibs

jsch.jar


Sample Application Packaging

debian/control

Source: salliere
Section: misc
Priority: optional
Maintainer: Matthew Johnson <mjj29@debian.org>
Build-Depends: debhelper (>= 5), default-jdk-builddep, fastjar,
               libmatthew-debug-java, libcsv-java,
               libitext-java, javahelper
Standards-Version: 3.7.3

Package: salliere
Architecture: all
Depends: ${java:Depends}, ${misc:Depends}
Description: Short Description
 Long Description


debian/rules

#!/usr/bin/make -f
export JAVA_HOME=/usr/lib/jvm/default-java
export CLASSPATH=/usr/share/java/csv.jar:/usr/share/java/debug-disable.jar:/usr
/share/java/itext.jar

build: build-stamp
build-stamp:
   dh_testdir
   # Build the package
   jh_build salliere.jar src
   touch $@

clean:
   dh_testdir
   dh_testroot
   jh_build --clean
   dh_clean
   rm -f build-stamp salliere.jar

install: build
   dh_testdir
   dh_testroot
   dh_clean -k
   dh_installdirs

binary-arch: build install
   # Java packages are arch: all, nothing to do here

binary-indep: build install
   # Create the package here
   dh_testdir
   dh_testroot
   dh_clean -k
   dh_install -i
   dh_installdocs -i
   dh_installchangelogs -i
   jh_manifest -i
   dh_link -i
   jh_exec -i
   jh_depends -i
   dh_compress -i
   dh_fixperms -i
   dh_installdeb -i
   dh_gencontrol -i
   dh_md5sums -i
   dh_builddeb -i

binary: binary-indep binary-arch
.PHONY: build clean binary-indep binary-arch binary install


debian/salliere.install

salliere.jar usr/share/salliere


debian/salliere.links

usr/share/salliere/salliere.jar usr/bin


