JButton.actionPerformed: null pointer exception

Question

I\'m working through a book, and the following code throws a NPE at runtime when the JButton is clicked, at the line button.actionPerformed. I\'ve done my best to be sure m

Answer 1

The reason is this Line:

JButton button = new JButton("click here");

Here you are creating new local JButton object which is shadowing the member variable button . Hence button is still null. You should instead use:

button = new JButton("click here");