的Java Swing空指针异常Netbeans IDE中

Question

我仍然相当新的Java和我已经开始使用秋千在NetBeans Java IDE的8.2一个简单的GUI项目和正在运行到一个空指针异常。

我已经去除了大部分代码下至底部，以试图找到其中的问题是来自和我仍然得到仅运行这些代码行异常。

package finalmodel;
import javax.swing.*;


public class FinalModel extends JFrame {

    public static void main (String[] args) {

        new FinalModel();
    }

    public FinalModel () {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);

    }

}

该应用程序运行正常，而据我所知，除了不影响功能（弹出一个窗口，可以从上面的代码被成功关闭），但异常在窗口的关闭抛出。

由IDE给我的堆栈跟踪

java.lang.NullPointerException: peer
    at sun.awt.windows.WInputMethod.openCandidateWindow(Native Method)
    at sun.awt.windows.WInputMethod.access$400(WInputMethod.java:45)
    at sun.awt.windows.WInputMethod$1.run(WInputMethod.java:602)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
    at java.awt.EventQueue$4.run(EventQueue.java:733)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
    at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159) [catch]
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)    
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)    
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)    
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)    
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Version Info

Answer 1

你的例子是很小的。它可能会丢失某些属性。试试这个：

package finalmodel;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class FinalModel extends JFrame {
 public FinalModel () {
   setTitle("setTitle()");
   setSize(300, 200);
   setLocationRelativeTo(null);
   setDefaultCloseOperation(EXIT_ON_CLOSE);
 }
 public static void main(String[] args) {
   FinalModel fm = new FinalModel ();
   fm.setVisible(true);
 }
}

这里的一对JFrame的好文章，实践jframes

Answer 2

NetBeans错误！重新安装NetBeans支持未更新的版本或类似的东西。