错误:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at test.factory.MainWindow.setFuncList(MainWindow.java:160)
at test.factory.MainWindow.<init>(MainWindow.java:22)
at test.factory.MainWindow$2.run(MainWindow.java:151)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:721)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:691)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
代码:
TestFactory tf = new TestFactory();
ArrayList<Function> fList = tf.getFunctions();
DefaultListModel<Function> dFuncList = new DefaultListModel();
fListPane.setModel(dFuncList);
for(Function f : fList) {
dFuncList.addElement(f);
}
<小时/>
问题:
现在,如果您发现错误那就太好了,但我的问题是。如何解析错误文本以找到错误的根源?我已经习惯了诸如 缺少 ';' 之类的事情位于 C:\filename 的第 24 行
更新: fList 有两个元素,因此不为 null。
最佳答案
错误转储是堆栈跟踪,因此我倾向于发现最好从顶部开始并向下进行。在本例中,MainWindow.java 第 160 行的 setFuncList 似乎正在尝试使用 null 对象(可能尚未初始化?)。
更新:有效的代码示例
class Function {
int i;
public Function(int myI) {
this.i = myI;
}
@Override
public String toString() {
return "i=" + this.i;
}
}
用于:
ArrayList<Function> fList = new ArrayList<>();
fList.add(new Function(1));
fList.add(new Function(2));
DefaultListModel<Function> dFuncList = new DefaultListModel();
jList2.setModel(dFuncList);
for(Function f : fList) {
dFuncList.addElement(f);
}
关于Java jList NullPointerException 错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15012790/