Nameless Nested Classes passed in Function Parameter?

Question

I am trying to get my head around the following code example:
javax.swing.SwingUtilities.invokeLater( new Runnable() { public void run() { createAndShowGUI(); }});What is actually getting passed to the SwingUtilities.invokeLater() function?
Can anyone explain all of the parts and pieces of :
new Runnable() { public void run() { createAndShowGUI(); }} ?
Here is my best guess:
1) { public void run() { createAndShowGUI(); }} is an unnamed nested class that is instantiated using the Runnable() interface.
2) this class has one method called run() that executes createAndShowGUI();
Is my best guess even close to what is really going on?

Answer 1

richard.broersma wrote:
1) { public void run() { createAndShowGUI(); }} is an unnamed nested class that is instantiated using the Runnable() interface.Yes, that's essentially correct. It's called an anonymous inner class.
This is similar to doing
// a non-anonymous inner class
private class MyClass implements Runnable
  public void run()
    createAndShowGUI();
MyClass myclass = new MyClass();
javax.swing.SwingUtilities.invokeLater(myclass);
2) this class has one method called run() that executes createAndShowGUI();Yes. It must have a parameterless public void run method since it implements the Runnable interface.
Is my best guess even close to what is really going on?Yes, you're catching on.