Install Java and Eclipse on UbuntuLinux

Install Java and Eclipse on UbuntuLinux-general Linux technology-Linux programming and kernel information. For details, refer to the following section. During Ubuntu installation, Java of the GNU version will be installed at the same time, just like in most Linux releases. This Java is too practical, especially for developers, it is not very useful. Installing SUN Java in Ubuntu is very easy. Step 1:

Sudo apt-get install sun-java5-jdk

After the installation is complete, select the default java:
Sudo update-alternatives -- config java

Then configure the environment variable:
Sudo vim/etc/environment

Add the following two lines:
CLASSPATH =/usr/lib/jvm/java-1.5.0-sun/lib
JAVA_HOME =/usr/lib/jvm/java-1.5.0-sun

Save and exit.

Install and configure Eclipse. Installation is simple:

Sudo apt-get install eclipse

Although the newly installed java has become the default jvm of the system, Eclipse does not use the jvm set by update-alternative to start itself. Instead, it uses the previous GNU Java. GNU Java is an implementation of 1.4.2, and its performance is far inferior to that of SUN. To enable Eclipse to start with SUN Java, we need to continue the configuration. First, set SUN Java to the default JDK:

Sudo update-java-alternatives-s java-1.5.0-sun

Then edit the JVM configuration file:
Sudo vim/etc/jvm

Convert
/Usr/lib/jvm/java-1.5.0-sun

This line moves to the top of the configuration block. Because Eclipse ignores Ubuntu's general Java settings (which looks like a bug), we need to edit the java_home file of Eclipse:

Sudo vim/etc/eclipse/java_home

As above
/Usr/lib/jvm/java-1.5.0-sun

This line moves to the top of the file.

After all the installation and configuration are completed, the Java Development Platform of Ubuntu is basically complete.