Can you please clarify the doubt in Exception.

Question

public class TraverseExceptionChain
    static public void traverseExceptionChain(Throwable t)
       while(t != null)
         System.out.println(t);
         t = t.getCause();
    public static void main(String args[])
       int array[] = new int[10];
        try
           array[500] = 1;
        catch(Exception e)
           Exception e2=new Exception("Two",e);
           Exception e3=new Exception("Three",e2);
           traverseExceptionChain(e3);
}O/P:
java.lang.Exception: Three
java.lang.Exception: Two
java.lang.ArrayIndexOutOfBoundsException: 500
Can any body explain program especially catch block???

Answer 1

Exception e3 has as cause e2 which has aa cause e, where having a cause means 'this exception is caused by another exception'.
Usually exceptions as wrapped like this to add extra information, while retaining the original exception information.