What kind of window are You talking about ? Is it java.awt.Window or javax.swing.JWindow or javax.swing.JFrame ? I am asking because I cannot find resizeTo() method in any of these classes ! If You mean javax.swing.JFrame.resize(), it is better not to use it because it's deprecated.
Hints: To resize window use jFrame.setSize(100,100) method. To maximize window use jFrame.setExtendedState(JFrame.MAXIMIZED_BOTH).