These guidelines are laid out in order of relevance to packaging.
Introduction
The Basics
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 .java
(source file) .class
(Java bytecode) .jar
(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 java
binary with a list of JAR files specifying the classpath like so:
java [-cp <jar1:jar2:jar3>] <main-class> [<args>]
Java Packaging
The 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: 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.
Package naming
Packages MUST follow the standard Fedora Packaging/NamingGuidelines.
Java API documentation MUST be placed into a sub-package called %{name}-javadoc
.
Release tags
Packages MUST follow the standard Fedora Package versioning guidelines.
JAR file installation
The following applies to all JAR files except JNI-using JAR files, 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).
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.
Filenames
- If the package provides a single JAR and the filename provided by the build is
%{name}.jar
or%{name}-%{version}.jar
then filename%{name}.jar
MUST be used. - If the package provides a single JAR and the filename provided by the build is neither
%{name}-%{version}.jar
nor%{name}.jar
then this file MUST be installed as%{name}.jar
and a symbolic link with the usual name must be provided. Alternatively, the file can be installed to the subdirectory%{_javadir}/%{name}/
. - 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
- All architecture-independent JAR files MUST go into
%{_javadir}
or a Java-version specific directory%{_javadir}-*
as appropriate[1]. Packages CAN place JAR files into subdirectories.
- For installation of architecture dependent jar files, see Packaging JAR files that use JNI
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 are named in the same way as original except addition of version to package name
- Jar and pom files MUST be versioned
Javadoc installation
- Java API documentation uses a system known as javadoc. All javadocs MUST be created and installed into a directory of
%{_javadocdir}/%{name}
. - Directory or symlink
%{_javadocdir}/%{name}-%{version}
SHOULD NOT exist. - The javadoc subpackage MUST be declared
noarch
even if main package is architecture specific.
BuildRequires and Requires
At a minimum, Java packages MUST:
BuildRequires: java-devel [>= specific_version] BuildRequires: jpackage-utils Requires: java [>= specific_version] Requires: jpackage-utils
For historical reasons, when specifying versions 1.6.0 or greater, an epoch of 1 must be included. Example:
Requires: java >= 1:1.6.0
build-classpath
build-classpath
is a script that can be used to generate classpaths from generic names of JAR files. Example:
export CLASSPATH=$(build-classpath commons-logging commons-net xbean/xbean-reflect)
build-jar-repository
build-jar-repository
is similar to build-classpath
but instead of producing a classpath entry, it creates symlinks in a given directory. Example:
$ 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
ant
ant
is a build tool used by many Java packages. Packages built using ant
ship with build.xml
files which contain build targets similar to Makefiles
. Packages built using ant
must:
BuildRequires: ant ... %build ... ant
Maven pom.xml files and depmaps
If upstream project is shipping Maven pom.xml
files, these MUST be installed. Additionally they MUST install corresponding depmaps.
If upstream project does not ship pom.xml file [official maven repo] should be checked and if there are pom.xml files they SHOULD be installed.
add_maven_depmap macro
This macro SHOULD be used only by non-maven packages and in case that the new techniques described in this document cannot be applied from some reason.
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 the %add_maven_depmap
macro. %add_maven_depmap
reads the groupId and artifactId from the pom file and creates a file in %{_mavendepmapfragdir}
that maps groupId:artifactId pairs to jar files under %{_javadir}
. All fragments in this directory are read by mvn-rpmbuild during startup, allowing the locally installed jar files and poms to be used as a maven repository.
Note that -- unless you use the -f
option as shown below -- all depmap fragments for a given package are written to the same file, %{_mavendepmapfragdir}/%{name}
. You should be sure to include this file in the %files
section of your RPM.
For the macro to work properly, all jar files must be copied into %{_javadir}
(see JAR file installation), and all pom files must be copied into %{_mavenpomdir}
and given file names of the following form, where jarname
is the name of the jar without the .jar suffix:
%{_mavenpomdir}/JPP[.subdirectory]-jarname.pom
Note that the subdirectory is only necessary if the jar file is put into a subdirectory of %{_javadir}
. For example:
- For junit, the jar is
%{_javadir}/junit.jar
, so the pom would be%{_mavenpomdir}/JPP-junit.pom
. - For plexus-ant-factory, the jar is
%{_javadir}/plexus/ant-factory.jar
, so the pom would named%{_mavenpomdir}/JPP.plexus-ant-factory.pom
.
If a pom is installed with no corresponding jar file -- for example, for parent poms -- the same convention should be followed:
- The Apache commons parent pom is installed in
%{_mavenpomdir}/JPP-commons-parent.pom
.
In its simplest form (a pom without a jar file), %add_maven_depmap
looks like this:
%add_maven_depmap JPP-%{name}.pom
This will read the pom file in question and provide a mapping between the groupId and artifactId inside the pom file and the pom file placed into %{_mavenpomdir}
.
For a pom that maps directly to a jar file, the following is the correct form:
%add_maven_depmap JPP-%{name}.pom %{name}.jar
In addition to creating the pom mapping, this will also ensure that the correct jar is associated with the groupId and artifactId from the pom.
%add_maven_depmap JPP-%{name}.pom %{name}.jar -a "org.apache.commons:commons-lang"
This form also adds additional mappings for given pom/jar file. For example, if the pom file indicates that it contains groupId commons-lang, artifactId commons-lang, this form ensures that we also add a mapping between groupId org.apache.commons and the installed jar/pom files. This is necessary in cases where the groupId or artifactId may have changed, and other packages might require different IDs than those reflected in the installed pom.
%add_maven_depmap JPP-%{name}.pom %{name}.jar -f "XXX"
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.
%add_maven_depmap JPP.%{name}-sub.pom %{name}/sub.jar
This form should be used when a package consists of multiple jar files that are installed into a subdirectory of %{_javadir}
. Note that in this case, the pom file name includes the optional subdirectory field.
Apache Maven
In Fedora 15 and newer, Maven 3 is used. Packages built using Maven ship with pom.xml
files. They SHOULD contain common sections such as the following:
BuildRequires: maven-local ... %build %mvn_build ... %install %mvn_install ... %files -f .mfiles
The macros %mvn_build
and %mvn_install
automatically handle building of the JAR files and their subsequent installation to the correct directory. The corresponding POM and depmap files are also installed.
Additional mappings
The macro %mvn_alias
can be used to add additional mappings for given POM/JAR file. For example, if the POM file indicates that it contains groupId commons-lang, artifactId commons-lang, this macro ensures that we also add a mapping between groupId org.apache.commons and the installed JAR/POM files. This is necessary in cases where the groupId or artifactId may have changed, and other packages might require different IDs than those reflected in the installed POM.
%mvn_alias "commons-lang:commons-lang" "org.apache.commons:commons-lang"
Alternative JAR file names
In some cases, it may be important to be able to provide symlinks to actual JAR files. This can be achieved with %mvn_file
macro. This macro allows packager to specify names of the JAR files, their location in %{_javadir}
directory and also can create symlinks to the JAR files. These symlinks can be possibly located outside of the %{_javadir}
directory.
Example of usage of %mvn_file
macro:
%prep ... %mvn_file :guice google/guice guice
This means that JAR file for artifact with ID "guice" (and any groupId) will be installed in %{_javadir}/google/guice.jar
and there also will be a symlink to this JAR file located in %{_javadir}/guice.jar
. Note the macro will add ".jar" extensions automatically.
Single artifact per package
If the project consists of multiple artifacts, it is recommended to install each artifact to the separate subpackage. The macro %mvn_build -s
will generate separate .mfiles
file for every artifact in the project. This file contains list of files related to specific artifact (typically JAR file, POM file and depmap). It can be later used in %files
section of the spec file.
Example:
... %description The Maven Plugin Tools contains... %package -n maven-plugin-annotations Summary: Maven Plugin Java 5 Annotations %description -n maven-plugin-annotations This package contains Java 5 annotations to use in Mojos. %package -n maven-plugin-plugin Summary: Maven Plugin Plugin %description -n maven-plugin-plugin The Plugin Plugin is used to... ... %build %mvn_build -s %install %mvn_install %files -f .mfiles-maven-plugin-tools %doc LICENSE NOTICE %files -n maven-plugin-annotations -f .mfiles-maven-plugin-annotations %files -n maven-plugin-plugin -f .mfiles-maven-plugin-plugin %files -f .mfiles-javadoc ...
Custom package layout
The package layout can be customized with %mvn_package
macro. This macro allows maintainer to specify exact package in which the selected artifact will end up.
Example:
... %prep %mvn_package ":plexus-compiler-jikes" plexus-compiler-extras %mvn_package ":plexus-compiler-eclipse" plexus-compiler-extras %mvn_package ":plexus-compiler-csharp" plexus-compiler-extras %build %mvn_build %mvn_install %files -f .mfiles %files -f .mfiles-plexus-compiler-extras %files -f .mfiles-javadoc
In above example, the artifacts plexus-compiler-jikes
, plexus-compiler-eclipse
, plexus-compiler-csharp
will end up in package named plexus-compiler-extras
. If there are some other artifacts beside these three mentioned (e.g. some parent POMs), then these will all end up in package named %{name}
.
{{admon/tip|Tip|%mvn_package
macro supports brace expansions, so whole %prep
section from previous example can be replaced with single line:
%mvn_package ":plexus-compiler-{jikes,eclipse,csharp}" plexus-compiler-extras
}}
Patching Maven pom.xml
files
Sometimes Maven pom.xml
files need to be patched before they are used to build packages. One could use traditional patches to maintain changes, but package maintainers SHOULD use %pom_*
macros developed specially to ease this task.
These macros are designed to be called from %prep
section of spec files. There are documented in /etc/rpm/macros.fjava
configuration file, which is also available online. See the documentation for technical details how to use these macros. Below are some examples added for convenience.
Often dependencies specified in Maven pom.xml
files need to be removed because of different reasons. %pom_remove_dep
macro can be used to ease this task:
# Removes dependency on groupId:artifactId from ./pom.xml %pom_remove_dep groupId:artifactId # Removes dependency on groupId:artifactId from ./submodule/pom.xml %pom_remove_dep groupId:artifactId submodule # Removes dependency on groupId:artifactId from ./full/path/to/file.pom %pom_remove_dep groupId:artifactId full/path/to/file.pom # Removes dependency on all artifacts in group groupId from ./pom.xml %pom_remove_dep groupId: # Removes all dependencies from ./pom.xml %pom_remove_dep :
%pom_remove_plugin
macro works exactly as %pom_remove_dep
, except it removes Maven plugin invocations. Some examples:
# Disables maven-jar-plugin so that classpath isn't included in manifests %pom_remove_plugin :maven-jar-plugin # Disable a proprietary plugin that isn't packaged for Fedora %pom_remove_plugin com.example.mammon:useless-proprietary-plugin submodule
Sometimes some submodules of upstream project cannot be built for various reasons and there is a need to disable them. This can be achieved by using %pom_disable_module
, for example:
# Disables child-module-1, a submodule of the main pom.xml file %pom_disable_module child-module-1 # Disables grandchild-module, a submodule of child-module-2/pom.xml %pom_disable_module grandchild-module child-module-2
The above macros cover the most common cases of modifying pom.xml
files, however if there is a need to apply some less-common patches there are also two generic macros for modifying pom.xml
files. %pom_xpath_remove
can be used to remove arbitrary XML nodes, described by XPath expressions. %pom_xpath_inject
macro is capable of injecting arbitrary XML code to any pom.xml
file. Below you can find some examples for these macros.
# Removes parent definition %pom_xpath_remove "pom:parent" # Removes extensions from the build %pom_xpath_remove "pom:build/pom:extensions" module/pom.xml # Adds new dependency %pom_xpath_inject "pom:dependencies" "<dependency><groupId>org.example.project</groupId><artifactId>awesomeproject</artifactId><version>1.0.0.GA</version></dependency>"
Using %pom_*
macros not only increases readability of the spec file, but also improves maintainability of the package as there are no patches that would need to be rebased with each upstream release.
Wrapper Scripts
Applications wishing to provide a convenient method of execution SHOULD provide a wrapper script in %{_bindir}
.
The jpackage-utils package contains a convenience %jpackage_script
macro that can be used to create scripts that work for the majority of packages. See its definition and documentation in /etc/rpm/macros.jpackage
. 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 true
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.
%install ... %jpackage_script com.sun.msv.driver.textui.Driver "" "" msv-msv:msv-xsdlib:relaxngDatatype:isorelax msv true ...
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 ":"). build-classpath
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
-devel
packages don't really make sense for Java packages. Header files do not exist for Java packages.
Specfile Template
ant
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
Apache Maven
Name: # see normal package guidelines Version: # see normal package guidelines Release: 1%{?dist} Summary: # see normal package guidelines License: # see normal package guidelines URL: # see normal package guidelines Source0: # see normal package guidelines BuildArch: noarch BuildRequires: java-devel [>= java version] BuildRequires: maven-local %description some smart and long description. %package javadoc Summary: API documentation for %{name} %description javadoc This package contains %{symmary}. %prep %setup -q %build %mvn_build %install %mvn_install %files -f .mfiles %doc %files javadoc -f .mfiles-javadoc %doc %changelog
Packaging and using EE APIs
There are a number of various project providing implementations for Java EE APIs. To simplify packaging and use of these APIs certain standardization is necessary.
EE API List
Following is a list of EE APIs as of Java EE 6[2] with chosen packages that provide implementations:
- javax.activation - JDK
- javax.annotation - JDK
- javax.el - tomcat-el-2.2-api
- javax.enterprise.inject - cdi-api
- javax.inject - atinject
- javax.jws - JDK
- javax.mail - javamail
- javax.management - JDK
- javax.management.remote - JDK
- javax.persistence - geronimo-jpa
- javax.security.auth.message - geronimo-jaspic-spec
- javax.servlet - tomcat-servlet-3.0-api
- javax.servlet.jsp - glassfish-jsp/glassfish-jsp-api
- javax.servlet.jsp.jstl - jakarta-taglibs-standard
- javax.transaction - JDK
- javax.ws.rs - jsr-311
- javax.wsdl - wsdl4j
- javax.xml - JDK
- javax.xml.bind - JDK
- javax.xml.rpc - axis
- javax.xml.soap - JDK
- javax.xml.stream - JDK
- javax.xml.ws - JDK
Packages providing APIs
In addition to following generic guidelines they MUST:
- Add Provides: javax.XXX from the EE API list
- Add directory %{_javadir}/javax.XXX that will contain symlinks to all implementation jar files and their dependencies
At one time there CAN BE multiple API implementations but there MUST be at most one package having specific javax.XXX virtual provide.
Packages using APIs
Packages that need to use EE API SHOULD use:
- Requires: javax.XXX from the EE API list
- build-classpath javax.XXX or equivalent instead of relying on package-specific jar name.
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.
Note that GCJ packages contain .so
s 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 CAN BE symlinked to%{_libdir}/%{name}
. - JNI shared objects MUST be placed in
%{_libdir}/%{name}
Example
To satisfy this Fedora requirement of using "System.load()" instead of "System.loadLibrary()" while still providing 32-bit versus 64-bit usability as well as complying with Java's write-once-run-anywhere goal, most JNI jar file should contain code similar to the following (as used in the pki-symkey JNI package):
static boolean tryLoad(String filename) { try { System.load(filename); } catch (Exception e) { return false; } catch (UnsatisfiedLinkError e) { return false; } return true; } // Load native library static { boolean mNativeLibrariesLoaded = false; String os = System.getProperty("os.name"); if ((os.equals("Linux"))) { // Check for 64-bit library availability // prior to 32-bit library availability. mNativeLibrariesLoaded = tryLoad("/usr/lib64/symkey/libsymkey.so"); if (mNativeLibrariesLoaded) { System.out.println("64-bit symkey library loaded"); } else { // REMINDER: May be trying to run a 32-bit app // on 64-bit platform. mNativeLibrariesLoaded = tryLoad("/usr/lib/symkey/libsymkey.so"); if (mNativeLibrariesLoaded) { System.out.println("32-bit symkey library loaded"); } else { System.out.println("FAILED loading symkey library!"); System.exit(-1); } } } else { try { System.loadLibrary("symkey"); System.out.println("symkey library loaded"); mNativeLibrariesLoaded = true; } catch (Throwable t) { // This is bad news, the program is doomed at this point t.printStackTrace(); } } }
Packages utilizing approach of bundling so files as resources within JAR files themselves do not have these issues and are more self-contained.
Notes on multiarch
Our guidelines have never been completely multiarch-aware. So it was never really possible to install both i686 and x86_64 JNI-using java libraries. However guidelines complicated things by introducing usage of %{_libdir} and other directories. This version makes it clear we do not support multiarch for JNI-using packages.
Some of the complications with multiarch for JNI packages are:
- build-classpath and related tools would need to be aware what will be architecture of executing JVM
- build-jar-classpath would still not work for creating symlinks because it would create them on build architecture instead of runtime architecture
- Previous reasons cause creating of /usr/bin wrappers impractical
- Handling proper requires in RPM is impossible. For example package Z-native.i686 and JDK.x86_64 are installed. As far as RPM is concerned this would be enough to provide Z.noarch with needed "Requires: Z-native", but it would not work during runtime.
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 Requires
. 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 %prep
(courtesy David Walluck):
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
Javadoc scriptlets
Older JPackage packages contained %post
scriptlets creating %ghost
symlinks. These MUST not appear in Fedora Java packages and are actively being removed at JPackage.
Selected rpmlint issues
class-path-in-manifest
Use sed
to remove class-path
elements in MANIFEST.MF
(or whatever file is being used as the JAR manifest) prior to JAR creation. Example:
sed -i '/class-path/I d' META-INF/MANIFEST.MF
Older packaging techniques
If possible, the packagers MUST use new techniques described previously in this document. However, there are situations where those cannot be applied. For example, if older, but still supported Fedora release doesn't support the recommended macros, it is still possible to use older techniques of building and installing of JAR/POM files.
Maven 3
From Fedora 15 to Fedora 18, maven 3 is used and the package is called maven
. Packages built using maven
ship with pom.xml
files. They SHOULD contain common sections such as the following:
... %build mvn-rpmbuild package 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 ... %check mvn-rpmbuild verify %files %{_mavendepmapfragdir}/%{name} %{_mavenpomdir}/JPP-%{name}.pom
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