: How to Install Java in Ubuntu

I At present, Java 5 and Java 6 are installed on my machine at the same time, so it is easy to switch between them. Java 6 has some good things, such as JSR-223 and jconsole, which I like to use better. For Java 5: Java 6: and other software packages that you may be interested in, Sun-Java 6-Demo Sun-Java 6-Doc Sun-Java 6-Source, please verify that you have the correct version of java running: To view the list of Java versions that you have installed, you can use the following command (with the letter L at the end of the command) : This should display a list of all Java replacement software that you have installed. Java-gcj is a free Java version of GNU project, which is installed with Ubuntu by default and should be visible. To switch to a different version, use the following command :sudo apt-get install sun-java5-jre sun-java5-jdke.g:sudo apt-get install sun-java6-jre sun-java6-jdk