JRE is Java Runtime Environment and is the machine-specific implementation of JVM. It contains libraries like rt.jar, class loaders etc which are used by JVM.

JDK, contains development tools and JRE.

Assuming you have installed Java in \usr\local\java\jdk directory −if you use bash as your shell, then you would add the following line to the end of your '.bashrc: export JAVA_HOME=\usr\local\java\jdk'Assuming you have stored your Java programs in \usr\local\myprograms\ directory −if you use bash as your shell, then you would add the following line to the end of your '.bashrc: export CLASSPATH=\usr\local\myprograms'.

Set pathAssuming you have installed Java in c:\Program Files\java\jdk directory −Right-click on 'My Computer' and select 'Properties'.Click the 'Environment variables' button under the 'Advanced' tab.Now, alter the 'Path' variable so that it also contains the path to the Java executable. Example, if the path is currently set to 'C:\WINDOWS\SYSTEM32', then change your path to read 'C:\WINDOWS\SYSTEM32;c:\Program Files\java\jdk\bin'.Set ClasspathAssuming you have stored your Java programs in c:\myprograms\ directory −Right-click on 'My Computer' and select 'Properties'.Click the 'Environment variables' button under the 'Advanced' tab.Now, add the 'CLASSPATH' variable and set the path to the c:\myprograms\'.Read More

Assuming you have installed Java in \usr\local\java\jdk directory −if you use bash as your shell, then you would add the following line to the end of your '.bashrc: export JAVA_HOME=\usr\local\java\jdk'

Assuming you have installed Java in \usr\local\java\jdk directory −if you use bash as your shell, then you would add the following line to the end of your '.bashrc: export JAVA_HOME=\usr\local\java\jdk'

Assuming you have installed Java in c:\Program Files\java\jdk directory −Right-click on 'My Computer' and select 'Properties'.Click the 'Environment variables' button under the 'Advanced' tab.Now, add the 'JAVA_HOME' variable and set the path to the c:\Program Files\java\jdk'.

Environment variable PATH should be set to point to where the Java binaries have been installed. Refer to your shell documentation if you have trouble doing this.Example, if you use bash as your shell, then you would add the following line to the end of your '.bashrc: export PATH=/path/to/java:$PATH'

Environment variable PATH should be set to point to where the Java binaries have been installed. Refer to your shell documentation if you have trouble doing this.Example, if you use bash as your shell, then you would add the following line to the end of your '.bashrc: export PATH=/path/to/java:$PATH'

Following are the required steps −Assuming you have installed Java in c:\Program Files\java\jdk directory −Right-click on 'My Computer' and select 'Properties'.Click the 'Environment variables' button under the 'Advanced' tab.Now, alter the 'Path' variable so that it also contains the path to the Java executable. Example, if the path is currently set to 'C:\WINDOWS\SYSTEM32', then change your path to read 'C:\WINDOWS\SYSTEM32;c:\Program Files\java\jdk\bin'.