Java in Gentoo: Difference between revisions
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* The java command on Gentoo honors the CLASSPATH variable. So often the best way to specify the classpath is via this variable. | * The java command on Gentoo honors the CLASSPATH variable. So often the best way to specify the classpath is via this variable. | ||
* Always remember than when using the -jar switch, java ignores both the -cp argument and the CLASSPATH. The classpath is built via the instructions on the Manifest file of your jar. | * Always remember than when using the -jar switch, java ignores both the -cp argument and the CLASSPATH. The classpath is built via the instructions on the Manifest file of your jar. The alternative is to not use jar, thus writing something like: | ||
java -cp "/path/my.jar" net.elvanor.main | |||
* Sometimes it can be useful to symlink to existing jars in the place where they are expected by a jar manifest. | * Sometimes it can be useful to symlink to existing jars in the place where they are expected by a jar manifest. | ||
Revision as of 06:40, 30 March 2015
Installing a JDK
- For some applications, you may need the jce USE flag set for the sun-jdk (Java Cryptography Extension). Note that emerging sun-jce-bin is not enough.
Libraries (JAR) locations
- Java packages are VERY often SLOTed.
- If a package is SLOTed, the jar go to /usr/share/package-name-SLOT/package-name.jar. Note that in the JAR there should not be any version number. Beware that some old/badly written ebuilds can forget to specify a SLOT, thus, the jar end in /usr/share/package-name/package-name.jar. This can be confusing when using java-config -p which report the location of the JAR (since it may mask the fact that another version of the package exist).
Classpath
- The java command on Gentoo honors the CLASSPATH variable. So often the best way to specify the classpath is via this variable.
- Always remember than when using the -jar switch, java ignores both the -cp argument and the CLASSPATH. The classpath is built via the instructions on the Manifest file of your jar. The alternative is to not use jar, thus writing something like:
java -cp "/path/my.jar" net.elvanor.main
- Sometimes it can be useful to symlink to existing jars in the place where they are expected by a jar manifest.