I am using Knoppix 3.8.1 and it is bundled with Java 1.4.2. I do not know how to uninstall Java 1.4 and since I need the new features of Java 1.5, I decided to install Java 1.5 over it (some of you may think its not a very good idea).

Now, when I run a java -version at the command prompt, it still says 1.4.2. So I explicitly exported the PATH of my new Java 1.5

"export PATH=/home/java1_5/bin"

After that "java -version" replies with 1.5, which is correct. However when I restart the shell, the PATH seems to be reset to its original state and won't recognize my Java 1.5!
Please help!