相关疑难解决方法(0)

考虑这些类:

class Parent {
 int a;
}

class Child extends Parent {
 int a; // error?
}

如果声明a中Child没有给出编译错误,由于多次声明int a？

WindowConstants 定义如下:

public interface WindowConstants
{
    public static final int DO_NOTHING_ON_CLOSE = 0;

    public static final int HIDE_ON_CLOSE = 1;

    public static final int DISPOSE_ON_CLOSE = 2;

    public static final int EXIT_ON_CLOSE = 3;

}

JFrame 定义如下:

public class JFrame  extends Frame implements WindowConstants,
                                              Accessible,
                                              RootPaneContainer,
                              TransferHandler.HasGetTransferHandler
{
    /**
     * The exit application default window close operation. If a window
     * has this set as the close operation and is closed in an applet,
     * a <code>SecurityException</code> may be thrown. …