EnableEvents (AWTEvent.WINDOW_EVENT_MASK); The Eclipse platform in the circles I write under a package of two categories. Then they wrote the first line of the constructor function enableEvents (AWTEvent.WINDOW_EVENT_MASK); This sentence Can be used in Class A, is java.awt.component.enableEvents (long args) In saying that no such category B, So strange and neighborhoods? (I type A and B both import java.awt.*;) The two types are inherited from the java.awt.Component? Is ah, is the same in all, we do not know why he had always being given in Eclipse, which began not reported [ Closed window ]