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These guidelines are laid out in order of relevance to packaging.
{{OldGuidelinePage|Java}}
{{DISPLAYTITLE:Fedora Packaging Guidelines for Java}}
<div style="float: right; margin-left: 0.5em" class="toclimit-2">__TOC__</div>


== Introduction ==
This page represents Fedora guidelines for packaging libraries and applications written in Java and related languages using Java Virtual Machine as bytecode interpreter. It does not aim to extensively describe packaging techniques and tips. RPM macros and commands used here are documented in man pages. Furthermore a separate [https://fedora-java.github.io/howto/latest/ Java Packaging HOWTO] describes Java packaging techniques in detail and includes examples, templates and documentation aimed at packagers and Java developers who are taking their first steps in Java RPM packaging.


=== The Basics ===
Fedora Java packaging is originally based on [http://www.jpackage.org JPackage Project] standards. Over time we have diverged in packaging tools in most areas but we mostly keep backward compatibility with older packages that make use of JPackage standards.
The term Java means many things to many people: a class library, a bytecode interpreter, a JIT compiler, a language specification, etc.  For the vast majority of users and developers, Java is a programming language and runtime environment that is architecture- and OS-agnostic.  The normal flow of code is <code>.java</code> (source file) <code>.class</code> (Java bytecode) <code>.jar</code> (a zip archive). In the majority of cases, a user executes a Java program by specifying a class name containing a main method (just like C and C++). Often, this is done by invoking the <code>java</code> binary with a list of JAR files specifying the classpath like so:


<code>java [-cp <jar1:jar2:jar3>]  <main-class> [<args>] </code>


== Java Packaging ==
== Package naming ==
The [http://www.jpackage.org JPackage Project]  has defined standard file system locations and conventions for use in Java packages.  Many distributions have inherited these conventions and in the vast majority of cases, Fedora follows them verbatim.  We include relevant sections of the JPackage guidelines here but caution that the canonical document will always reside upstream:  [http://www.jpackage.org/cgi-bin/viewvc.cgi/src/jpackage-utils/doc/jpackage-1.5-policy.xhtml?revision=HEAD&root=jpackage JPackage Guidelines]  .  Over time, we would like to remove any divergences in these documents, but where they are different, these Fedora guidelines will take precedence for Fedora packages.


TODO: Find the proper jpackage link and fix it.
Packages MUST follow the standard Fedora [[Packaging/NamingGuidelines | package naming guidelines]].


=== Package naming ===
Java API documentation MUST be placed into a sub-package called <code>%{name}-javadoc</code>.


Packages '''MUST''' follow the standard Fedora [[Packaging/NamingGuidelines]].
== Release tags ==
Packages MUST follow the standard Fedora [[Packaging/NamingGuidelines#Package_Versioning | package versioning guidelines]].


Java API documentation '''MUST''' be placed into a sub-package called <code>%{name}-javadoc</code>.
== Pre-built dependencies ==
Packages MUST follow the standard Fedora [[Packaging:Guidelines#No_inclusion_of_pre-built_binaries_or_libraries | dependency bundling guidelines]].


==== Release tags ====
In particular <code>*.class</code> and <code>*.jar</code> files from upstream releases MUST NOT be used during build of Fedora packages and they MUST NOT be included in binary RPM.
Packages '''MUST''' follow the standard Fedora [[Packaging/NamingGuidelines#Package_Version | Package versioning guidelines]] .


=== JAR file installation ===
== JAR file installation ==


The following applies to all JAR files except [[#JNI|JNI-using JAR files]], [[#GCJ|GCJ files]] and application-specific JAR files (ie. JAR files that can only reasonably be used as part of an application and therefore constitute application-private data).
The following applies to all JAR files except [[#JNI|JNI-using JAR files]] and application-specific JAR files (ie. JAR files that can only reasonably be used as part of an application and therefore constitute application-private data).


==== Split JAR files ====
=== Split JAR files ===


If a project offers the choice of packaging it as a single monolithic jar or several ones, the split packaging '''should''' be preferred.
If a project offers the choice of packaging it as a single monolithic JAR or several ones, the split packaging SHOULD be preferred.


==== Filenames ====
=== Installation directory ===


* If the package provides a '''single''' JAR and the filename provided by the build is <code>%{name}.jar</code> or <code>%{name}-%{version}.jar</code> then filename <code>%{name}.jar</code> '''MUST''' be used.
* All architecture-independent JAR files MUST go into <code>%{_javadir}</code> or its subdirectory.
* If the package provides a '''single''' JAR and the filename provided by the build is neither <code>%{name}-%{version}.jar</code> nor <code>%{name}.jar</code> then this file '''MUST''' be installed as <code>%{name}.jar</code> and a symbolic link with the usual name must be provided.
* If the package provides more than '''one''' JAR file, the filenames assigned by the build '''MUST''' be used (without versions).
* If the project usually provides alternative JAR file names by installing symbolic links then such symlinks '''MAY''' be installed in the same directory as the JAR files.


==== Installation directory ====
* For installation of architecture dependent JAR files, see [[#Packaging_JAR_files_that_use_JNI|Packaging JAR files that use JNI]].


* All JAR files '''MUST''' go into <code>%{_javadir}</code> or a Java-version specific directory <code>%{_javadir}-<i>*</i></code> as appropriate[http://lists.fedoraproject.org/pipermail/packaging/2010-January/006792.html].
=== Filenames ===


* If the number of provided JAR files exceeds '''two''', you '''MUST''' place them into a sub-directory named <code>%{name}</code>.
* If the package provides a '''single''' JAR file installed filename SHOULD be <code>%{name}.jar</code>.
* If the package provides '''multiple''' JAR files, they SHOULD be installed in a <code>%{name}</code> subdirectory
* Versioned JAR files (<code>*-%{version}.jar</code>) MUST NOT be installed unless the package is a compatibility package
* Packages MAY provide alternative filenames as long as they do not conflict with other packages


=== Javadoc installation ===


* Java API documentation uses a system known as javadoc.  All javadocs '''MUST''' be created and installed into a directory of <code>%{_javadocdir}/%{name}</code>.
{{admon/note|Note|Here %{name} refers either to package name, or name of subpackage where the jar is installed.}}
* Directory or symlink <code>%{_javadocdir}/%{name}-%{version}</code> '''SHOULD NOT''' exist.
* The javadoc subpackage '''MUST''' be declared <code>noarch</code> even if main package is architecture specific.


=== BuildRequires and Requires ===
== BuildRequires and Requires ==
At a minimum, Java packages '''MUST''':
Java packages MUST BuildRequire their respective build system:
* <code>BuildRequires: maven-local</code> for packages built with Maven
* <code>BuildRequires: ant</code> for packages built with ant
* <code>BuildRequires: java-devel</code> for packages built with javac


<pre>BuildRequires: java-devel [>= specific_version]
Java binary packages or their dependencies MUST have Requires (generated by RPM or manual) on:
BuildRequires:  jpackage-utils
* <code>java-headless</code> or <code>java-headless >= 1:minimal_required_version</code>
* <code>javapackages-filesystem</code>


Requires: java >= specific_version
If java-headless requirement is insufficient package MUST have Requires:
Requires: jpackage-utils</pre>
* <code>java</code> or <code>java >= 1:minimal_required_version</code>


For historical reasons, when specifying versions 1.6.0 or greater, an epoch of 1 must be included.  Example:
== Javadoc installation ==


<pre>Requires: java >= 1:1.6.0
* javadoc documentation MAY be generated
</pre>
* If javadoc documentation is generated it MUST be installed into a directory of <code>%{_javadocdir}/%{name}</code> as part of javadoc subpackage
* Directory or symlink <code>%{_javadocdir}/%{name}-%{version}</code> SHOULD NOT exist.
* The javadoc subpackage MUST be declared <code>noarch</code> even if main package is architecture specific.


=== build-classpath ===
== No class-path in MANIFEST.MF ==
<code>build-classpath</code> is a script that can be used to generate classpaths from generic names of JAR files. Example:
* JAR files MUST NOT include <code>class-path</code> entry inside META-INF/MANIFEST.MF


<pre>export CLASSPATH=$(build-classpath commons-logging commons-net xbean/xbean-reflect)
== Hardcoded paths ==
</pre>
Packages MUST NOT hardcode paths to JAR files they use.  When package needs to reference a JAR file, packager SHOULD use one of tools designed to locating JAR files in the system.
{{admon/note|Additional information|You can use either package names (all jar files will be included) or jar filenames with path prefix to select only some jar files from whole package.}}


=== build-jar-repository ===
== Maven pom.xml files ==
<code>build-jar-repository</code> is similar to <code>build-classpath</code> but instead of producing a classpath entry, it creates symlinks in a given directory.  Example:
If upstream project is shipping Maven <code>pom.xml</code> files, these MUST be installed. Additionally package MUST install mapping between upstream artifact and filesystem by using the <code>%mvn_install</code> macro.
<pre>$ mkdir lib
$ build-jar-repository -s -p lib commons-logging commons-net
$ ls -l lib
commons-logging.jar -> /usr/share/java/commons-logging.jar
commons-net.jar -> /usr/share/java/commons-net.jar
</pre>


=== ant ===
{{admon/note|Additional documentation|Additional artifact installation documentation is available for[https://fedora-java.github.io/howto/latest/#ant Ant projects] and [https://fedora-java.github.io/howto/latest/#maven Maven projects].}}
<code>ant</code> is a build tool used by many Java packages. Packages built using <code>ant</code> ship with <code>build.xml</code> files which contain build targets similar to <code>Makefiles</code>. Packages built using <code>ant</code> must:


<pre>BuildRequires: ant
...
%build
...
ant
</pre>


=== maven2 ===
If upstream project does not ship Maven <code>pom.xml</code> file, official [http://mvnrepository.com/ maven repository] should be searched and if there are <code>pom.xml</code> files they SHOULD be installed.
In Fedora 14 and older (including EPEL), the package is called <code>maven2</code>. Packages built using <code>maven</code> ship with <code>pom.xml</code> files. They '''MUST''':


<pre>Requires(post): jpackage-utils
If modifications to Maven pom.xml files are needed <code>%pom_*</code> family of macros SHOULD be used
Requires(postun): jpackage-utils</pre>


and '''SHOULD''' contain common sections such as the following:
{{admon/note|Additional documentation|Usage of %pom_* macros is documented in detail in [https://fedora-java.github.io/howto/latest/#helper_macros Java Packaging HOWTO].}}


<pre>
== Wrapper Scripts ==
...
Applications wishing to provide a convenient method of execution SHOULD provide a wrapper script in <code>%{_bindir}</code>. Packages SHOULD use <code>%jpackage_script</code> to create these wrapper scripts.
%build
export MAVEN_REPO_LOCAL=$(pwd)/.m2/repository
mkdir -p $MAVEN_REPO_LOCAL


mvn-jpp \
{{admon/note|Additional documentation|Usage of %jpackage_script macro is documented in [https://fedora-java.github.io/howto/latest#_generating_application_shell_scripts Java Packaging HOWTO].}}
-Dmaven.repo.local=$MAVEN_REPO_LOCAL \
install javadoc:javadoc
...


%install
== Compatibility packages ==
install -d -m 755 $RPM_BUILD_ROOT%{_javadir}
In certain cases it might be necessary to create compatibility packages that provide older API/ABI level of the same library. However creating these compatibility packages is strongly discouraged. To standardize and simplify packaging of such compatibility packages following rules apply:
install -d -m 755 $RPM_BUILD_ROOT%{_mavenpomdir}
install -pm 644 pom.xml $RPM_BUILD_ROOT/%{_mavenpomdir}/JPP-%{name}.pom
# artifactId and jarName are usually %{name} for single module projects
%add_to_maven_depmap [groupId] [artifactId] %{version} JPP[/optional_subDir] [jarName]


...
* Compatibility packages MUST be named in the same way as original except addition of version to package name,
%post
* Any JAR and POM files MUST be versioned.
%update_maven_depmap


%postun
{{admon/note|Ant and Maven compatibility|build-classpath and related tools will resolve versioned jar files if versioned jar is asked for. Maven will use dependency information will return versioned jar if it matches the version asked for in the pom file.}}
%update_maven_depmap
...
</pre>
 
{{admon/note|Note:|Multimodule Maven projects should use javadoc:aggregate instead of javadoc:javadoc.}}
 
{{admon/important|Important|Please read [[Java/JPPMavenReadme]] for details about mvn-jpp and %add_to_maven_depmap usage. }}
 
=== maven3 ===
In Fedora 15 and newer, maven 3 is used and the package is called <code>maven</code>.  Packages built using <code>maven</code> ship with <code>pom.xml</code> files.  They '''SHOULD''' contain common sections such as the following:
 
<pre>
...
%build
mvn-rpmbuild install javadoc:aggregate
...
 
%install
install -d -m 755 $RPM_BUILD_ROOT%{_javadir}
install -d -m 755 $RPM_BUILD_ROOT%{_mavenpomdir}
install -pm 644 pom.xml $RPM_BUILD_ROOT/%{_mavenpomdir}/JPP-%{name}.pom
install -pm 644 target/%{name}-%{version}.jar $RPM_BUILD_ROOT/%{_javadir}/%{name}.jar
 
# second argument is optional (parent poms have no jars)
%add_maven_depmap JPP-%{name}.pom %{name}.jar
...
%files
%{_mavendepmapfragdir}/%{name}
%{_mavenpomdir}/JPP-%{name}.pom
</pre>
 
Useful mvn-rpmbuild customisations:
* -Dmaven.local.depmap.file=FILE.xml - xml file that defines alternative dependency maps
* -Dmaven.local.debug=true makes custom resolver output more debugging information
 
{{admon/important|Important|Fedora 15+ have both Maven 3.X and Maven 2.2.1 (packages maven and maven2 respectively). Only maven package contains mvn-rpmbuild. Maven 2 is considered deprecated and is included to ensure backward compatibility. Use of maven2 is strongly discouraged in Fedora 15 and newer.}}
 
{{admon/important|Important|For detailed instructions on use of add_maven_depmap macro see [[#depmap_macro|macro documentation]]}}
 
=== add_maven_depmap macro ===
{{Anchor|depmap_macro}}
 
Maven identifies jar files by a set of strings: groupId, artifactId and version (mostly). To let mvn-rpmbuild know what groupId:artifactId corresponds to which pom or jar file we use %add_maven_depmap macro. In its simplest form add_maven_depmap looks like this:
<pre>%add_maven_depmap JPP-%{name}.pom</pre>
This will read pom file in question and provide mapping between groupId,artifactId inside pom file and pom file placed into %{_mavenpomdir}. Given pom file already has to exist inside %{_mavenpomdir}. Mapping is stored inside %{_mavendepmapfragdir}/%{name} file. All mappings (fragments) are read by mvn-rpmbuild during startup. This form should only be used for pom-only artifacts (i.e. parent poms).
 
<pre>%add_maven_depmap JPP-%{name}.pom %{name}.jar</pre>
In addition to creating mapping, this will also ensure that jar and pom files are named correctly and placed in correct subdirectories.
 
<pre>%add_maven_depmap JPP-%{name}.pom %{name}.jar -a "org.apache.commons:commons-lang"</pre>
This form also adds additional mappings for given pom/jar file. I.e. if pom file stated it contains groupId commons-lang, artifactId commons-lang, by using this form we also added mapping between groupId org.apache.commons and jar/pom files.
 
<pre>%add_maven_depmap JPP-%{name}.pom %{name}.jar -f "XXX"</pre>
This form stores dependency mapping inside %{_mavendepmapfragdir}/%{name}-XXX instead of standard location. This is useful for packages with multiple subpackages where each has its own jar files.
 
=== Wrapper Scripts ===
Applications wishing to provide a convenient method of execution '''SHOULD''' provide a wrapper script in <code>%{_bindir}</code>. 
 
The jpackage-utils package contains a convenience <code>%jpackage_script</code> macro that can be used to create scripts that work for the majority of packages.  See its definition and documentation in <code>/etc/rpm/macros.jpackage</code>.  One thing to pay attention to is the 6th argument to it - whether to prefer a JRE over a full SDK when looking up a JVM to invoke - most packages that don't require the full Java SDK will want to set that to <code>true</code> to avoid unexpected results when looking up a JVM when some of the installed JRE's don't have the corresponding SDK (*-devel package) installed.
 
<pre>
%install
...
%jpackage_script com.sun.msv.driver.textui.Driver "" "" msv-msv:msv-xsdlib:relaxngDatatype:isorelax msv true
...
</pre>
The previous example installs the "msv" script (5th argument) with main class being com.sun.msv.driver.textui.Driver (1st argument). No optional flags (2nd argument) or options (3rd argument) are used. This script will add several libraries to classpath before executing main class (4th argument, jars separated with ":"). <code>build-classpath</code> is run on every part of 4th argument to create full classpaths.
 
=== GCJ ===
Building GCJ AOT bits is discouraged unless you have a very strong reason to include them in the packages.
Even when AOT bits are built and included in packages it is recommended to not require java-1.5.0-gcj because this will force every single user to install it even if one wants to use another JVM.
 
Please refer to [[Packaging/GCJGuidelines]]  for GCJ-specific guidelines.
 
=== -devel packages ===
<code>-devel</code> packages don't really make sense for Java packages.  Header files do not exist for Java packages.
 
 
=== Maven pom.xml files and depmaps ===
If upstream project is shipping Maven pom.xml files, these '''MUST''' be installed with the corresponding %add_maven_depmap calls.
 
If upstream project does not ship pom.xml file [[http://repo1.maven.org/maven2/ official maven repo]] should be checked and if there are pom.xml files they '''SHOULD''' be installed.
 
{{admon/tip|Tip|[http://mvnrepository.com/ Mvnrepository site] can be used to ease}}
 
== Specfile Template ==
=== ant ===
 
<pre>
Name:          # see normal package guidelines
Version:        # see normal package guidelines
Release:        1%{?dist}
Summary:        # see normal package guidelines
 
Group:          # see normal package guidelines
License:        # see normal package guidelines
URL:            # see normal package guidelines
Source0:        # see normal package guidelines
BuildArch:      noarch
 
BuildRequires:  jpackage-utils
 
BuildRequires:  java-devel
 
BuildRequires:  ant
 
Requires:      jpackage-utils
 
Requires:      java
 
%description
 
%package javadoc
Summary:        Javadocs for %{name}
Group:          Documentation
Requires:      jpackage-utils
 
%description javadoc
This package contains the API documentation for %{name}.
 
%prep
%setup -q
 
find -name '*.class' -exec rm -f '{}' \;
find -name '*.jar' -exec rm -f '{}' \;
 
%build
ant
 
%install
 
mkdir -p $RPM_BUILD_ROOT%{_javadir}
cp -p [build path to jar] $RPM_BUILD_ROOT%{_javadir}/%{name}.jar
 
mkdir -p $RPM_BUILD_ROOT%{_javadocdir}/%{name}
cp -rp [javadoc directory] $RPM_BUILD_ROOT%{_javadocdir}/%{name}
 
%files
%{_javadir}/*
%doc
 
%files javadoc
%{_javadocdir}/%{name}
 
 
%changelog
</pre>
 
 
 
=== maven 2 ===
{{admon/important|Important|Fedora 15+ have both Maven 3.X and Maven 2.2.1 packaged (packages maven and maven2 respectively). Maven 2 is considered deprecated and is included to ensure backward compatibility. Use of maven2 is strongly discouraged, however, older Fedora releases (and EPEL) still require its use.}}
 
<pre>
Name:          # see normal package guidelines
Version:        # see normal package guidelines
Release:        1%{?dist}
Summary:        # see normal package guidelines
 
Group:          # see normal package guidelines
License:        # see normal package guidelines
URL:            # see normal package guidelines
Source0:        # see normal package guidelines
 
BuildArch:      noarch
 
BuildRequires:  jpackage-utils
 
BuildRequires:  java-devel
 
BuildRequires:  maven2
 
BuildRequires:    maven-compiler-plugin
BuildRequires:    maven-install-plugin
BuildRequires:    maven-jar-plugin
BuildRequires:    maven-javadoc-plugin
BuildRequires:    maven-release-plugin
BuildRequires:    maven-resources-plugin
BuildRequires:    maven-surefire-plugin
 
Requires:      jpackage-utils
 
Requires(post):      jpackage-utils
Requires(postun):    jpackage-utils
 
Requires:      java
 
%description
some smart and long description.
 
%package javadoc
Summary:        Javadocs for %{name}
Group:          Documentation
Requires:      jpackage-utils
 
%description javadoc
This package contains the API documentation for %{name}.
 
%prep
%setup -q
 
%build
 
export MAVEN_REPO_LOCAL=$(pwd)/.m2/repository
mkdir -p $MAVEN_REPO_LOCAL
 
mvn-jpp -Dmaven.repo.local=$MAVEN_REPO_LOCAL \
        install javadoc:javadoc # or javadoc:aggregate
 
%install
 
mkdir -p $RPM_BUILD_ROOT%{_javadir}
cp -p [build path to jar] $RPM_BUILD_ROOT%{_javadir}/%{name}.jar
 
mkdir -p $RPM_BUILD_ROOT%{_javadocdir}/%{name}
cp -rp [javadoc directory] $RPM_BUILD_ROOT%{_javadocdir}/%{name}
 
install -d -m 755 $RPM_BUILD_ROOT%{_mavenpomdir}
install -pm 644 [path to pom]  \
        $RPM_BUILD_ROOT%{_mavenpomdir}/JPP-%{name}.pom
 
%add_to_maven_depmap project_group_id project_artifact_id %{version} JPP %{name}
 
 
%post
%update_maven_depmap
 
%postun
%update_maven_depmap
 
 
%files
%{_mavenpomdir}/*
%{_mavendepmapfragdir}/*
%{_javadir}/*
%doc
 
%files javadoc
%{_javadocdir}/%{name}
 
%changelog
 
</pre>
 
{{admon/important|Depmap information|Last two arguments to %add_to_maven_depmap macro represent location of installed jar file. Using ".. jpp/foo bar" as last two arguments will mean that groupId/artifactId of package will resolve to jar file %{_javadir}/foo/bar.jar.}}
For detailed instructions on the JPackage/Fedora maven, see the JPackage Maven rpm readme located [http://fedoraproject.org/wiki/Java/JPPMavenReadme here] .
 
=== maven 3 ===
{{admon/important|Important|Only Fedora 15 and newer releases have Maven 3. For older releases and EPEL, refer to the maven 2 template.}}
 
<pre>
Name:          # see normal package guidelines
Version:        # see normal package guidelines
Release:        1%{?dist}
Summary:        # see normal package guidelines
 
Group:          # see normal package guidelines
License:        # see normal package guidelines
URL:            # see normal package guidelines
Source0:        # see normal package guidelines
 
BuildArch:      noarch
 
BuildRequires:  jpackage-utils
 
BuildRequires:  java-devel
 
BuildRequires:  maven
 
BuildRequires:    maven-compiler-plugin
BuildRequires:    maven-install-plugin
BuildRequires:    maven-jar-plugin
BuildRequires:    maven-javadoc-plugin
BuildRequires:    maven-release-plugin
BuildRequires:    maven-resources-plugin
BuildRequires:    maven-surefire-plugin
 
Requires:      jpackage-utils
Requires:      java
 
%description
some smart and long description.
 
%package javadoc
Summary:        Javadocs for %{name}
Group:          Documentation
Requires:      jpackage-utils
 
%description javadoc
This package contains the API documentation for %{name}.
 
%prep
%setup -q
 
%build
mvn-rpmbuild install javadoc:aggregate
 
%install
 
mkdir -p $RPM_BUILD_ROOT%{_javadir}
cp -p [build path to jar] $RPM_BUILD_ROOT%{_javadir}/%{name}.jar
 
mkdir -p $RPM_BUILD_ROOT%{_javadocdir}/%{name}
cp -rp [javadoc directory] $RPM_BUILD_ROOT%{_javadocdir}/%{name}
 
install -d -m 755 $RPM_BUILD_ROOT%{_mavenpomdir}
install -pm 644 [path to pom]  \
        $RPM_BUILD_ROOT%{_mavenpomdir}/JPP-%{name}.pom
 
%add_maven_depmap JPP-%{name}.pom %{name}.jar
 
 
%files
%{_mavenpomdir}/JPP-%{name}.pom
%{_mavendepmapfragdir}/%{name}
%{_javadir}/%{name}.jar
%doc
 
%files javadoc
%{_javadocdir}/%{name}
 
%changelog
 
</pre>
 
{{admon/important|Important|For detailed instructions on use of add_maven_depmap macro see [[#depmap_macro|macro documentation]]}}


== Packaging JAR files that use JNI ==
== Packaging JAR files that use JNI ==
Line 451: Line 101:
=== Applicability ===
=== Applicability ===


Java programs that wish to make calls into native libraries do so via the Java Native Interface (JNI).  A Java package uses JNI if it contains a .so
Java programs that wish to make calls into native libraries do so via the Java Native Interface (JNI).  A Java package uses JNI if it contains a .so file. Note that this file can be embedded within JAR files themselves.


{{Template:Warning}} Note that GCJ packages contain <code>.so</code>s in <code>%{_libdir}/gcj/%{name}</code> but they are not JNI .sos.
{{Template:Warning}} Note that GCJ packages contain <code>.so</code>s in <code>%{_libdir}/gcj/%{name}</code> but they are not JNI .sos.
Line 457: Line 107:
=== Guideline ===
=== Guideline ===


JAR files that require JNI shared objects '''MUST''' be installed in <code>%{_libdir}/%{name}</code>.  The JNI shared objects themselves must also be installed in <code>%{_libdir}/%{name}</code>. If the JNI-using code calls <code>System.loadLibrary</code> you'll have to patch it to use <code>System.load</code>, passing it the full path to the dynamic shared object.  If the package installs a wrapper script you'll need to manually add <code>%{_libdir}/%{name}/<jar filename></code> to <code>CLASSPATH</code>.  If you are depending on a JNI-using JAR file, you'll need to add it manually -- <code>build-classpath</code> will not find it.
* JNI packages MUST follow guidelines of ordinary Java packages with exceptions listed here
* JAR files using JNI or containing JNI shared objects themselves MUST be placed in <code>%{_jnidir}</code> and MAY be symlinked to <code>%{_libdir}/%{name}</code>.
* JNI shared objects MUST be placed in <code>%{_libdir}/%{name}</code>  


=== Rationale ===
{{admon/note|Note|If the JNI-using code calls <code>System.loadLibrary</code> you'll have to patch it to use <code>System.load</code>, passing it the full path to the dynamic shared object. You can look at the [[JavaSystemLoadExample|example]].}}


This is less convenient, but cleaner from a packaging point-of-view, than putting the JAR file in <code>%{_javadir}</code>, and putting the JNI shared object in  <code>%{_libdir}</code> to be loaded from the default library path.  First, JNI shared objects are <code>dlopen</code>'d, and <code>dlopen</code>'d shared objects should not be placed directly in <code>%{_libdir}</code> since they are application-private data, and not libraries meant to be linked to directly -- that is, not meant to be shared. Second, placing the JAR file in <code>%{_javadir}</code> causes the build-classpath script to always load it, even when running on a runtime environment of the wrong arch, meaning that the <code>System.loadLibrary</code> line would fail.
{{admon/note|Macro expansions|<code>%{_jnidir}</code> expands into <code>%{_prefix}/lib/java</code>, even on 64-bit systems. Java packages using JNI do not support multiarch installation.}}


The plan is to eventually eliminate patching of the <code>System.loadLibrary</code> line and wrapper script by making <code>jpackage-utils</code> multilib aware.  This involves the following changes:  creating <code>%{_libdir}/java</code> and <code>%{_libdir}/jni</code> directories; giving JNI-containing packages the ability to require an architecture-specific runtime environment; adding support for specifying the required runtime architecture in a wrapper script; modifying <code>jpackage-utils</code>'s runtime scripts to search <code>%{_libdir}/java</code>; modifying IcedTea to look for JNI shared objects in <code>%{_libdir}/jni</code>.


The <code>%{_jnidir}</code> rpm macro defines the main JNI jar repository. Like <code>%{_javadir}</code> it is declined in <code>-ext</code> and <code>-x.y.z</code> variants. It follows exactly the same rules as the <code>%{_javadir}</code>-derived tree structure, except that it hosts JAR files that use JNI.


<code>%{_jnidir}</code> usually expands into <code>/usr/lib/java</code>.
== Things to avoid ==
=== Pre-built JAR files / Other bundled software ===
Many Java projects re-ship their dependencies in their own releases.  This is unacceptable in Fedora.  All packages '''MUST''' be built from source and '''MUST''' enumerate their dependencies with <code>Requires</code>.  They '''MUST NOT''' build against or re-ship the pre-included JAR files but instead symlink out to the JAR files provided by dependencies.  There may arise rare cases that an upstream project is distributing JAR files that are actually not re-distributable
by Fedora.  In this situation, the JAR files themselves should not be redistributed -- even in the source zip.  A modified source zip should be created with some sort of modifier in the name (ex. -CLEAN) along with instructions for reproducing.  It is a good idea to have something similar to the following at the end of <code>%prep</code> (courtesy David Walluck):
<pre>
JAR files=""
for j in $(find -name \*.jar); do
if [ ! -L $j ] ; then
JAR files="$JAR files $j"
fi
done
if [ ! -z "$JAR files" ] ; then
echo "These JAR files should be deleted and symlinked to system JAR files: $JAR files"
exit 1
fi
</pre>
=== Javadoc scriptlets ===
Older JPackage packages contained <code>%post</code> scriptlets creating <code>%ghost</code> symlinks.  These '''MUST''' not appear in Fedora Java packages and are actively being removed at JPackage.
=== Selected rpmlint issues ===
==== class-path-in-manifest ====
Use <code>sed</code> to remove <code>class-path</code> elements in <code>MANIFEST.MF</code> (or whatever file is being used as the JAR manifest) prior to JAR creation.  Example:
<pre>
sed -i '/class-path/I d' META-INF/MANIFEST.MF
</pre>


[[Category:Java]]
[[Category:Packaging guidelines]]
[[Category:Packaging guidelines]]
[[Category:Java]]

Latest revision as of 20:18, 21 December 2018

Warning.png
This is an old copy of a packaging guideline, preserved here in the wiki while we complete the transition to the Fedora documentation system. The current version is located at https://docs.fedoraproject.org/en-US/packaging-guidelines/Java/. Please update your bookmarks.

This page represents Fedora guidelines for packaging libraries and applications written in Java and related languages using Java Virtual Machine as bytecode interpreter. It does not aim to extensively describe packaging techniques and tips. RPM macros and commands used here are documented in man pages. Furthermore a separate Java Packaging HOWTO describes Java packaging techniques in detail and includes examples, templates and documentation aimed at packagers and Java developers who are taking their first steps in Java RPM packaging.

Fedora Java packaging is originally based on JPackage Project standards. Over time we have diverged in packaging tools in most areas but we mostly keep backward compatibility with older packages that make use of JPackage standards.


Package naming

Packages MUST follow the standard Fedora package naming guidelines.

Java API documentation MUST be placed into a sub-package called %{name}-javadoc.

Release tags

Packages MUST follow the standard Fedora package versioning guidelines.

Pre-built dependencies

Packages MUST follow the standard Fedora dependency bundling guidelines.

In particular *.class and *.jar files from upstream releases MUST NOT be used during build of Fedora packages and they MUST NOT be included in binary RPM.

JAR file installation

The following applies to all JAR files except JNI-using JAR files and application-specific JAR files (ie. JAR files that can only reasonably be used as part of an application and therefore constitute application-private data).

Split JAR files

If a project offers the choice of packaging it as a single monolithic JAR or several ones, the split packaging SHOULD be preferred.

Installation directory

  • All architecture-independent JAR files MUST go into %{_javadir} or its subdirectory.

Filenames

  • If the package provides a single JAR file installed filename SHOULD be %{name}.jar.
  • If the package provides multiple JAR files, they SHOULD be installed in a %{name} subdirectory
  • Versioned JAR files (*-%{version}.jar) MUST NOT be installed unless the package is a compatibility package
  • Packages MAY provide alternative filenames as long as they do not conflict with other packages


Note.png
Note
Here %{name} refers either to package name, or name of subpackage where the jar is installed.

BuildRequires and Requires

Java packages MUST BuildRequire their respective build system:

  • BuildRequires: maven-local for packages built with Maven
  • BuildRequires: ant for packages built with ant
  • BuildRequires: java-devel for packages built with javac

Java binary packages or their dependencies MUST have Requires (generated by RPM or manual) on:

  • java-headless or java-headless >= 1:minimal_required_version
  • javapackages-filesystem

If java-headless requirement is insufficient package MUST have Requires:

  • java or java >= 1:minimal_required_version

Javadoc installation

  • javadoc documentation MAY be generated
  • If javadoc documentation is generated it MUST be installed into a directory of %{_javadocdir}/%{name} as part of javadoc subpackage
  • Directory or symlink %{_javadocdir}/%{name}-%{version} SHOULD NOT exist.
  • The javadoc subpackage MUST be declared noarch even if main package is architecture specific.

No class-path in MANIFEST.MF

  • JAR files MUST NOT include class-path entry inside META-INF/MANIFEST.MF

Hardcoded paths

Packages MUST NOT hardcode paths to JAR files they use. When package needs to reference a JAR file, packager SHOULD use one of tools designed to locating JAR files in the system.

Maven pom.xml files

If upstream project is shipping Maven pom.xml files, these MUST be installed. Additionally package MUST install mapping between upstream artifact and filesystem by using the %mvn_install macro.

Note.png
Additional documentation
Additional artifact installation documentation is available forAnt projects and Maven projects.


If upstream project does not ship Maven pom.xml file, official maven repository should be searched and if there are pom.xml files they SHOULD be installed.

If modifications to Maven pom.xml files are needed %pom_* family of macros SHOULD be used

Note.png
Additional documentation
Usage of %pom_* macros is documented in detail in Java Packaging HOWTO.

Wrapper Scripts

Applications wishing to provide a convenient method of execution SHOULD provide a wrapper script in %{_bindir}. Packages SHOULD use %jpackage_script to create these wrapper scripts.

Note.png
Additional documentation
Usage of %jpackage_script macro is documented in Java Packaging HOWTO.

Compatibility packages

In certain cases it might be necessary to create compatibility packages that provide older API/ABI level of the same library. However creating these compatibility packages is strongly discouraged. To standardize and simplify packaging of such compatibility packages following rules apply:

  • Compatibility packages MUST be named in the same way as original except addition of version to package name,
  • Any JAR and POM files MUST be versioned.
Note.png
Ant and Maven compatibility
build-classpath and related tools will resolve versioned jar files if versioned jar is asked for. Maven will use dependency information will return versioned jar if it matches the version asked for in the pom file.

Packaging JAR files that use JNI

Applicability

Java programs that wish to make calls into native libraries do so via the Java Native Interface (JNI). A Java package uses JNI if it contains a .so file. Note that this file can be embedded within JAR files themselves.

Stop (medium size).png Note that GCJ packages contain .sos in %{_libdir}/gcj/%{name} but they are not JNI .sos.

Guideline

  • JNI packages MUST follow guidelines of ordinary Java packages with exceptions listed here
  • JAR files using JNI or containing JNI shared objects themselves MUST be placed in %{_jnidir} and MAY be symlinked to %{_libdir}/%{name}.
  • JNI shared objects MUST be placed in %{_libdir}/%{name}
Note.png
Note
If the JNI-using code calls System.loadLibrary you'll have to patch it to use System.load, passing it the full path to the dynamic shared object. You can look at the example.
Note.png
Macro expansions
%{_jnidir} expands into %{_prefix}/lib/java, even on 64-bit systems. Java packages using JNI do not support multiarch installation.
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