Difference between revisions of "Java"
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Revision as of 12:37, 15 March 2013
"Java is a programming language originally developed by Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture." — Wikipedia article
- 1 Installation
- 2 Troubleshooting
- 3 Tips and tricks
The only JVM implementation in supported repositories is the open source OpenJDK. Additional Java implementations are available via the AUR. Keep in mind that the open-source and closed-source versions cannot be installed simultaneously. The open-source version is nearly perfect at the time of writing, and there is mostly no need anymore to install Oracle's proprietary version of Java.
To be able to run Java programs, you can install Java runtime with the package , available in the official repositories. There is also a Java Development Kit in . As of March 2013
openjdk6 is no longer available.
Flagging OpenJDK packages as out-of-date
Please flag packages IcedTea version (2.3.4) rather than on their Oracle version (u9). IcedTea-web projects (packages and ) have version numbers that are independant from the IcedTea one (packages , and ) so please flag each package based on its right version number., and as out-of-date based on their
Prior to the retirement of the Oracle DLJ, it was possible to simply install the AUR and AUR packages from the repositories. However, now Arch Linux (and any other GNU/Linux distribution) can no longer package the Oracle implementation of Java. The OpenJDK packages are the recommended providers of
Oracle JVM (Java 6)
AUR contains package forAUR and AUR, which are the Oracle implementations of Java SE 6. These packages conflict with the other java packages, so there are also AUR and AUR which can be used along side other java installations.
Kaffe is another clean-room implementation of a Java VM without official endorsement from Sun/Oracle. A git package of Kaffe can be found in the AUR here: AUR. The Kaffe VM is redistributed according to the GPL license.
BEA JRockit JIT JVM (+JDK)
JRockit is JIT version of Java, provided by Oracle and available from the AUR here: AUR.
VMkit LLVM-based JIT VM
VMkit is an LLVM-based framework for JIT virtual machines. J3 is a JVM running on VMkit. The webpage can be found here: [vmkit]. J3 depends on the GNU classpath libraries, but may also work with the Apache class path libraries.
The Parrot VM offers experimental support for Java through two different methods: Either as a Java VM bytecode translator or as a Java compiler targeting the Parrot VM. Available in the AUR package AUR.
Due to the fact that the JDBC-drivers often use the port in the URL to establish a connection to the database, it is considered "remote" (i.e., MySQL does not listen to the port as per its default settings) despite the fact that they are possibly running on the same host, Thus, to use JDBC and MySQL you should enable remote access to MySQL, following instructions in MySQL article.
Java sound with Pulseaudio
By default, Java and Pulseaudio do not get along very well with each other, but this is easy to fix using padsp.
(These paths are correct for Sun's Java, you will need to change the paths for OpenJDK)
First, rename the
java binary to
# mv /opt/java/jre/bin/java /opt/java/jre/bin/java.bin
Then, create a new launcher script at
#!/bin/sh padsp /opt/java/jre/bin/java.bin "$@"
Finally, make the launcher script executable
# chmod +x /opt/java/jre/bin/java
You will need to redo this process on each update of Java.
You can also try replacing padsp with aoss, which can also fix it under standard ALSA as well as in Pulse, do what works best. I must warn everyone that these hacks sometimes work perfect, but are sometimes very unstable as well.
Impersonate Another Window Manager
$ wmname LG3D
(You must restart the application in question after issuing the wmname command.)
This works because the JVM contains a hard-coded list of known non-re-parenting window managers. For maximum irony, many users prefer to impersonate “
LG3D,” the non-re-parenting window manager written by Sun, in Java.
Fonts are Illegible
In addition to the suggestions mentioned below in [tips and tricks] some fonts may still not be legible afterwards. If this is the case there is a good chance ms-fonts are being used. Install AUR from the AUR.
Tips and tricks
Behavior of most Java applications can be controlled by supplying predefined variables to Java runtime. From this forum post, a way to do it consists of adding the following line in your
/etc/profile.d/jre.sh to affect all users):
export _JAVA_OPTIONS="-D<option 1> -D<option 2>..."
For example, to use system anti-aliased fonts and make swing use the GTK look and feel:
export _JAVA_OPTIONS='-Dawt.useSystemAAFontSettings=on -Dswing.aatext=true -Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel'
Better font rendering
Both closed source and open source implementations of Java are known to have improperly implemented anti-aliasing of fonts. This can be fixed with the following options:
If your Java programs look ugly, you may want to set up the default look and feel for the swing components:
Some stubborn Java programs insist on using the cross platform Metal look and feel. In some of these cases you can force these apps to use the GTK look and feel by setting the following property:
Typically, OpenJDK installation creates symlinks in
/usr/bin for java, javac ... etc. If you want to change these symlinks to any other JDK (e.g. if you installed environment-compat packages of Oracle JDK), this script might be handy for you.