如下Exception in thread "AWT-EventQueue-0" ？什么情况

Question

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.CellRendererPane.addImpl(CellRendererPane.java:85)
at java.awt.Container.add(Container.java:365)
at javax.swing.plaf.basic.BasicListUI.updateLayoutState(BasicListUI.java:1350)
at javax.swing.plaf.basic.BasicListUI.maybeUpdateLayoutState(BasicListUI.java:1299)
at javax.swing.plaf.basic.BasicListUI.getPreferredSize(BasicListUI.java:566)
at javax.swing.JComponent.getPreferredSize(JComponent.java:1632)
at javax.swing.ScrollPaneLayout.layoutContainer(ScrollPaneLayout.java:769)
at java.awt.Container.layout(Container.java:1421)
at java.awt.Container.doLayout(Container.java:1410)
at java.awt.Container.validateTree(Container.java:1507)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validateTree(Container.java:1513)
at java.awt.Container.validate(Container.java:1480)
at java.awt.Window.dispatchEventImpl(Window.java:2473)
at java.awt.Component.dispatchEvent(Component.java:4413)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)

Answer 1

在swing某个线程中你发生了数组越界在异常栈中寻找你自己写的函数，找到第一个进去，看是哪一行出错了，然后跟踪调试核心就是，你必然在某处操作使得你程序中的某一数组越界了

Answer 2

空指针异常，比如FileOutputStream stream=new FileOutputStream(new File("C:/document.txt");stream.write("asdfg".getBytes());但是在C盘下并没有这样一个document.txt文件，就会出现这种异常