Java/Swing: Obtain Window/JFrame from inside a JPanel

You could use SwingUtilities.getWindowAncestor(...) method that will return a Window that you could cast to your top level type.

JFrame topFrame = (JFrame) SwingUtilities.getWindowAncestor(this);

There are 2 direct, different methods for this in SwingUtilities which provide the same functionality (as noted in their Javadoc). They return java.awt.Window but if you added your panel to a JFrame, you can safely cast it to JFrame.

The 2 direct and most simple ways:

JFrame f1 = (JFrame) SwingUtilities.windowForComponent(comp);
JFrame f2 = (JFrame) SwingUtilities.getWindowAncestor(comp);

For completeness some other ways:

JFrame f3 = (JFrame) SwingUtilities.getAncestorOfClass(JFrame.class, comp);
JFrame f4 = (JFrame) SwingUtilities.getRoot(comp);
JFrame f5 = (JFrame) SwingUtilities.getRootPane(comp).getParent();

JFrame frame = (JFrame)SwingUtilities.getRoot(x);

As other commentators already mentioned it is not generally valid to simply cast to JFrame. That does work in most special cases, but I think the only correct answer is f3 by icza in https://stackoverflow.com/a/25137298/1184842

JFrame f3 = (JFrame) SwingUtilities.getAncestorOfClass(JFrame.class, comp);

because this is a valid and safe cast and nearly as simple as all other answers.