关于抽象方法Toolkit.getScreenSize()的困惑
以下程序片段用于获取当前屏幕尺寸：
Toolkit kit=new Toolkit.getDefaultToolkit();
Dimension screenSize=kit.getScreenSize();
请教各位大虾，getScreenSize()是抽象方法，并没有定义功能，怎么还可以调用？这里是不是调用了Toolkit的子类中覆写的getScreenSize()？如果是的话，这里的子类是哪个？
[解决办法]
下面是kit.getScreenSize()方法的实现
public static synchronized Toolkit getDefaultToolkit() {
if (toolkit == null) {
try {
// We disable the JIT during toolkit initialization. This
// tends to touch lots of classes that aren't needed again
// later and therefore JITing is counter-productiive.
java.lang.Compiler.disable();
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction() {
public Object run() {
String nm = null;
Class cls = null;
try {
nm = System.getProperty("awt.toolkit", "sun.awt.X11.XToolkit");
try {
cls = Class.forName(nm);
} catch (ClassNotFoundException e) {
ClassLoader cl = ClassLoader.getSystemClassLoader();
if (cl != null) {
try {
cls = cl.loadClass(nm);
} catch (ClassNotFoundException ee) {
throw new AWTError("Toolkit not found: " + nm);
}
}
}
if (cls != null) {
toolkit = (Toolkit)cls.newInstance();
if (GraphicsEnvironment.isHeadless()) {
toolkit = new HeadlessToolkit(toolkit);
}
}
} catch (InstantiationException e) {
throw new AWTError("Could not instantiate Toolkit: " + nm);
} catch (IllegalAccessException e) {
throw new AWTError("Could not access Toolkit: " + nm);
}
return null;
}
});
loadAssistiveTechnologies();
} finally {
// Make sure to always re-enable the JIT.
java.lang.Compiler.enable();
}
}
return toolkit;
}
