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problem:linux:ubuntu_java

Ubuntu Java

By default Ubuntu runs GCJ, the GNU Java, instead of Sun's Java.

The 'easiest' way to enable Sun's Java is to run it from your launcher. For example:

/usr/lib/jvm/java-1.5.0-sun/bin/java -Dplugins.dir=/home/<YOURHOME>/ImageJ 
    -Xmx128m -cp /opt/ImageJ/ij.jar:/usr/lib/jvm/java-1.5.0-sun/lib/tools.jar ij.ImageJ

this command line specifies the location of your plugins directory (-Dplugins.dir), sets memory to 128 Mb (-Xmx128m) and allows plugins to be compiled (/usr/lib/jvm/java-1.5.0-sun/lib/tools.jar). Note that this is for Sun's Java 1.5 - it will need to be changed accordingly to the version you are running.

Additionally, you can export the Java classpath in your .bashrc:

export PATH=/usr/lib/jvm/java-1.5.0-sun/bin:$PATH

making sure that your 'JAVA_HOME' is set to the proper folder in your .bashrc:

export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun

Or make an alias in your .bashrc for 'java':

alias java='/usr/lib/jvm/java-1.5.0-sun/bin/java'

(Based on Albert Cardona's email to the mailing list.)

A Debian-based repository can also be used, contributed and tested by Paolo Ariano. It can be downloaded from: http://www.personalweb.unito.it/paolo.ariano/software.html

Java Installation on an Ubuntu based system

First install the Java version you want/need:

sudo apt-get install sun-java6-jre sun-java6-plugin sun-java6-fonts

replace the 6 by 5, if you need a Java 5. You can also replace the jre by jdk if you want a javac.

To change the default java command:

sudo update-alternatives --config java

and select the Version you want.

You can check the result by:

user@ubuntu:~$ java -version
java version "1.5.0_15"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_15-b04)
Java HotSpot(TM) Server VM (build 1.5.0_15-b04, mixed mode)
problem/linux/ubuntu_java.txt ยท Last modified: 2019/04/12 13:13 (external edit)