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. - 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].
- If the number of provided JAR files exceeds two, you SHOULD place them into a sub-directory named
%{name}
.
- 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 files MUST NOT be unversioned
- Base name of versioned jar files MUST be the same as original package jars and they MUST be placed alongside original jar files
- Package SHOULD NOT provide maven fragments or pom files
Compatibility package example
- Original package: plexus-container-2.0.0
Name: plexus-container Version: 2.0.0 ... %files ... %{_javadir}/plexus/container.jar %{_mavenpomdir}/JPP.plexus-container.pom %{_mavendepmapfragdir}/%{name} ...
- Compat package: plexus-container1-1.5.0
Name: plexus-container15 Version: 1.5.0 ... %files ... %{_javadir}/plexus/container-1.5.0.jar ...
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
maven3
In Fedora 15 and newer, 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 ... %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
add_maven_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 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.
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.
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 [official maven repo] should be checked and if there are pom.xml files they SHOULD be installed.
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
maven 3
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 package 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
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]:
- javax.activation
- javax.annotation
- javax.el
- javax.inject
- javax.jws
- javax.mail
- javax.management
- javax.management.remote
- javax.persistence
- javax.security.auth.message
- javax.servlet
- javax.servlet.jsp
- javax.servlet.jsp.jstl
- javax.transaction
- javax.ws.rs
- javax.wsdl
- javax.xml
- javax.xml.bind
- javax.xml.rpc
- javax.xml.soap
- javax.xml.stream
- javax.xml.ws
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 MUST be at most one package providing given API.
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
Note that GCJ packages contain .so
s in %{_libdir}/gcj/%{name}
but they are not JNI .sos.
Guideline
JAR files that require JNI shared objects MUST be installed in %{_libdir}/%{name}
. The JNI shared objects themselves must also be installed in %{_libdir}/%{name}
. 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. If the package installs a wrapper script you'll need to manually add %{_libdir}/%{name}/<jar filename>
to CLASSPATH
. If you are depending on a JNI-using JAR file, you'll need to add it manually -- build-classpath
will not find it.
Rationale
This is less convenient, but cleaner from a packaging point-of-view, than putting the JAR file in %{_javadir}
, and putting the JNI shared object in %{_libdir}
to be loaded from the default library path. First, JNI shared objects are dlopen
'd, and dlopen
'd shared objects should not be placed directly in %{_libdir}
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 %{_javadir}
causes the build-classpath script to always load it, even when running on a runtime environment of the wrong arch, meaning that the System.loadLibrary
line would fail.
The plan is to eventually eliminate patching of the System.loadLibrary
line and wrapper script by making jpackage-utils
multilib aware. This involves the following changes: creating %{_libdir}/java
and %{_libdir}/jni
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 jpackage-utils
's runtime scripts to search %{_libdir}/java
; modifying IcedTea to look for JNI shared objects in %{_libdir}/jni
.
The %{_jnidir}
rpm macro defines the main JNI jar repository. Like %{_javadir}
it is declined in -ext
and -x.y.z
variants. It follows exactly the same rules as the %{_javadir}
-derived tree structure, except that it hosts JAR files that use JNI.
%{_jnidir}
usually expands into /usr/lib/java
.
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