McGill University School of Computer Science
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Java

From Socs Info Wiki

This document provides information related to Java on computer systems at the School of Computer Science, of McGill University.

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Java versions on GNU/Linux lab machines

All Gentoo GNU/Linux lab machines at SOCS currently have the following versions of Java:

1.4.2, 1.5.0

The latest version, 1.5, is NOT the system default, instead 1.4.2 is. You can select a non-default version using the program "java-config".

To see what JVMs are available, use the "-L" flag... 

$ java-config -L
1) Blackdown JDK 1.4.2.03 [blackdown-jdk-1.4.2] (/usr/share/java-config-2/vm/blackdown-jdk-1.4.2)
*) Blackdown JRE 1.4.2.03 [blackdown-jre-1.4.2] (/usr/share/java-config-2/vm/blackdown-jre-1.4.2)
3) IBM JDK 1.4.2.5 [ibm-jdk-bin-1.4] (/usr/share/java-config-2/vm/ibm-jdk-bin-1.4)
4) IBM JDK 1.5.0.2 [ibm-jdk-bin-1.5] (/usr/share/java-config-2/vm/ibm-jdk-bin-1.5)
5) Sun JDK 1.4.2.12 [sun-jdk-1.4] (/usr/share/java-config-2/vm/sun-jdk-1.4)
6) Sun JDK 1.5.0.08 [sun-jdk-1.5] (/usr/share/java-config-2/vm/sun-jdk-1.5)

The selected version (for the system) is the one with an asterisk ("*") at the start of the line.

To determine what version is selected, use the "-f" flag... 

$ java-config -f
blackdown-jdk-1.4.2.02

To select a different version, use the "-s" flag, using either the number at the start of the line, or the string in the square brackets... 

$ java-config -s 6

or 

$ java-config -s sun-jdk-1.5

This sets the user-specific JVM by putting all necessary environment variables into $HOME/.gentoo/java-env and $HOME/.gentoo/java-env.csh. You will then need to source the file appropriate to your shell ("java-env" is for "sh" and "bash" shells, and "java-env.csh" is for "csh" and "tcsh" shells).

If you have not changed your shell initialization from the defaults, then you do not have to do anything.

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Java versions on FreeBSD lab machines

All FreeBSD lab machines at SOCS currently have the following versions of Java:

1.4.2, 1.5.0 in both NATIVE and LINUX INSTALLS

The latest version NATIVE, 1.5, is the system default.

The available JVMs are: 

/usr/local/diablo-jdk1.5.0
/usr/local/jdk1.4.2
/usr/local/jdk1.5.0
/usr/local/linux-sun-jdk1.4.2
/usr/local/linux-sun-jdk1.5.0

To determine what version you are using run: 

java -version
java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build diablo-1.5.0-b00)
Java HotSpot(TM) Client VM (build diablo-1.5.0_07-b00, mixed mode)

To set your version set your environment to one of the directories above:

With the default tcsh shell: 

In your .cshrc add:
setenv JAVA_HOME /usr/local/jdk1.4.2

For bash users: 

In your .bashrc
export JAVA_HOME=/usr/local/jdk1.4.2
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