I am using JDK 1.4.1. After installing the fresh copy of the JDK 1.4.1 in my system the Java programs work properly. But for the second time onwards whenever I run the Java program using "Java" it is giving the error "Exception in thread "main" java.lang.NoClassDefFoundError:Hello". I have tried for JDK 1.5 also, I got the same error. How to rectify this problem. Plz provide the solution.