Getting java.lang.NullPointerException when calling Method.invoke

Question

I\'m following this tutorial on Java annotaitons and implemented the Test annotation as shown there. But when running the code I get the following output.

java.l         


        

Answer 1

This issue is here:

method.invoke(null);

This method's first parameter is the object to invoke the method on. This is the dynamic (reflection) equivalent of something like this:

Object foo = null;
foo.toString();

Of course we would expect this code to give a NullPointerException because foo is null.