Java

"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." [1]

Installation

There are two Java Virtual Machines in the Arch repos that can be installed on your system — the OpenJDK open source implementation and Sun's closed source implementation. Arch recommends OpenJDK.. Additional Java implementations are available via the AUR.

OpenJDK JVM

To be able to run Java programs, you can install OpenJDK from the repositories. This also installs a Java Development Kit.

# pacman -Syu openjdk6

You will likely need the icedtea-web for Java functionality in Firefox as suggested in this thread: https://bbs.archlinux.org/viewtopic.php?pid=895343

# pacman -Syu icedtea-web

Note: If you experience any problems with the Java plugin, you can try the solution suggested for the Firefox Flash plugin: Flash#Plugins_are_installed_but_not_working

Note: If you use a non-reparenting window manager, you should uncomment the corresponding line in /etc/profile.d/openjdk6.sh

Oracle JVM

To be able to run Java programs, you can install the Oracle JRE from the repositories:

# pacman -S jre

You will need to log out and login again, or add /opt/java/jre/bin/ to $PATH to use the java bash command.

To create Java programs, you can install the Oracle JDK from the repositories:

# pacman -S jdk

Note: If you experience any problems with the Java plugin, you can try the solution suggested for the Firefox Flash plugin: Flash#Plugins_are_installed_but_not_working

Note: For Oracle Java, you will need to source /etc/profile in order to for the JAVA_HOME path to point to the correct place

# source /etc/profile

Apache Harmony

Apache Harmony is a clean room re-implementation of the Java language and comes under the Free Apache licence. A binary re-distribution of the Harmony JRE can be found in the AUR.

Kaffe

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. The Kaffe VM is redistributed according to the GPL license.

BEA JRockit JIT JVM (+JDK)

You can also install JIT version of Java from the AUR. jrockit

VMkit LLVM-based JIT VM

VMkit is an LLVM-based framework for JIT virtual machines. J3 is a JVM running on VMkit. A broken build for VMkit can be found in the AUR. J3 depends on the GNU classpath libraries, but may also work with the Apache class path libraries.

Parrot VM

The Parrot VM offers experimental support for Java through two different methods: Either as a Java VM bytecode translator or as a Java compiler targetting the Parrot VM.

Java sound with Pulseaudio

By default, Java and Pulseaudio don't 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 java.bin

# mv /opt/java/jre/bin/java /opt/java/jre/bin/java.bin

Then, create a new launcher script at /opt/java/jre/bin/java

#!/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.

Additional notes

MySQL

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 need to edit /etc/mysql/my.cnf and comment out the line looking like this:

 skip-networking

Read the article about MySQL for more information.