java - ExceptionInInitializerError，如何定位错误位置

Question

我收到了ExceptionInInitializerError。我被告知“getException() 方法现在被称为原因，并且可以通过 Throwable.getCause() 方法以及前面提到的“旧版本”进行访问。方法。""调用 getCause()"如何将这些方法应用到我的代码中以查找错误？例如，我是否只是将其放在类(class)的开头？周围有 try catch 吗？有我可以看到的例子吗？谢谢，

编辑:好的，这是整个错误日志:

CacheEntry[file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar]: updateAvailable=false,lastModified=Sat Mar 22 11:39:02 PDT 2014,length=225068
0
CacheEntry[file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar]: updateAvailable=false,lastModified=Sat Mar 22 11:39:02 PDT 2014,length=225068
Trace level set to 5: all ... completed.ui: Pushing modality for applet ID 14 with dialog sun.plugin.util.PluginSysUtil$DummyDialog[dialog0,-100,-100,132x38,layout=java.awt.BorderLayout,APPLICATION_MODAL,title=,defaultCloseOperation=HIDE_ON_CLOSE,rootPane=javax.swing.JRootPane[,3,25,126x10,layout=javax.swing.JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true]
basic: Dialog type is not candidate for embedding
ui: Pushing modality for applet ID 14 with dialog javax.swing.JDialog[dialog1,425,258,516x190,layout=java.awt.BorderLayout,TOOLKIT_MODAL,title=Application Error,defaultCloseOperation=HIDE_ON_CLOSE,rootPane=javax.swing.JRootPane[,3,25,510x162,layout=javax.swing.JRootPane$RootLayout,alignmentX=0.0,alignmentY=0.0,border=,flags=16777673,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true]
basic: PluginMain.unregisterApplet: 14 from mananger sun.plugin2.applet.Applet2Manager@1d9024f
preloader: Construct preloader delegate
preloader: Setting default preloader and progress monitor for non JNLP applets
basic: Added progress listener: sun.plugin.util.ProgressMonitorAdapter@124f232
preloader: Installing progress monitor true
basic: Plugin2ClassLoader.addURL parent called for file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar
network: Cache entry found [url: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar, version: null] prevalidated=false/0
cache: Adding MemoryCache entry: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar
cache: Resource file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar has expired.
network: ResponseCode for file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar : 200
network: Encoding for file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar : null
CacheEntry[file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar]: updateAvailable=false,lastModified=Sat Mar 22 11:39:02 PDT 2014,length=225068
cache: Reading Signers from 5 file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar | C:\Users\Camtronius\AppData\LocalLow\Sun\Java\Deployment\cache\6.0\50\7023cb32-6e9bc9fb.idx
network: No certificate info for unsigned JAR file: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar
cache: Done readSigners(file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar)
cache:  Read manifest for file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar: read=194 full=194
preloader: Using preloader class: null com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter@d4ba66
preloader: Using default preloader
preloader: Requested to use preloader class: null
ruleset: Non-jnlp rule id: 
        title: sonomaroller/SonomaRoller
        location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/AppletTest.html
        jar location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar
        jar version: null
        isArtifact: true
ruleset: finding Deployment Rule Set for 
        title: sonomaroller/SonomaRoller
        location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/AppletTest.html
        jar location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/sonomaroller/SonomaRoller.jar
        jar version: null
        isArtifact: true
ruleset: no rule applies, returning Default Rule
network: Created version ID: 1.7.0.51
network: Created version ID: 1.7.0.51
network: Created version ID: 1.7.0.51
network: Created version ID: 1.7.0.51
ruleset: Non-jnlp rule id: 
        title: sonomaroller/SonomaRoller
        location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/AppletTest.html
        jar location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/
        jar version: null
        isArtifact: true
ruleset: finding Deployment Rule Set for 
        title: sonomaroller/SonomaRoller
        location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/AppletTest.html
        jar location: file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/
        jar version: null
        isArtifact: true
ruleset: no rule applies, returning Default Rule
security: SSV validation:
    running: 1.7.0_51
    requested: null
    range: null
    javaVersionParam: null
    Rule Set version: null
network: Created version ID: 1.7.0.51
network: Created version ID: 1.7.0.51
security: continue with running version
network: Created version ID: 1.7.0.51
network: Created version ID: 1.7
network: Created version ID: 2.2.51
security:  --- parseCommandLine converted : 
into:
[]
preloader: Added pending event 1: AppletInitEvent[type=CallConstructor]
preloader: Delivering: AppletInitEvent[type=CallConstructor]
preloader: Skipped all (0) download events prior to null
preloader: Start progressCheck thread
preloader: GrayBox: parent = sun.plugin2.main.client.PluginEmbeddedFrame[frame2,0,0,550x550,layout=java.awt.BorderLayout,title=,resizable,normal]
basic: exception: java.lang.reflect.InvocationTargetException.
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter.runOnEDTAndWait(Unknown Source)
    at com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter.instantiateApplet(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager.initAppletAdapter(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException
    at com.sun.deploy.uitoolkit.impl.awt.OldPluginAWTUtil.invokeAndWait(Unknown Source)
    ... 5 more
Caused by: java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "exitVM.0")
    at java.security.AccessControlContext.checkPermission(Unknown Source)
    at java.security.AccessController.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkPermission(Unknown Source)
    at sun.plugin2.applet.AWTAppletSecurityManager.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkExit(Unknown Source)
    at javax.swing.JFrame.setDefaultCloseOperation(Unknown Source)
    at sonomaroller.SonomaRoller.<init>(SonomaRoller.java:19)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at java.lang.Class.newInstance(Unknown Source)
    at com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter$1.run(Unknown Source)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)
preloader: Delivering: ErrorEvent[url=file:/C:/Users/Camtronius/Documents/NetBeansProjects/SonomaRoller/build/classes/ label=java.lang.reflect.InvocationTargetException cause=java.lang.reflect.InvocationTargetException
basic: Removed progress listener: sun.plugin.util.ProgressMonitorAdapter@124f232
preloader: Preloader shutdown after ErrorEvent
preloader: Stop progressCheck thread
ui: Show default error panel
security: Reset deny session certificate store
basic: PluginMain.unregisterApplet: 15 from mananger sun.plugin2.applet.Applet2Manager@18f9ba9

Answer 1

Caused by: java.security.AccessControlException: access denied 
    ("java.lang.RuntimePermission" "exitVM.0")

这是异常的根本原因。在小程序中看到这种情况的最常见原因是小程序创建一个 JFrame 并调用:

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

这应该用DISPOSE_ON_CLOSE调用。如果在框架关闭时退出 JVM，它将结束运行该小程序的 JVM，以及在同一 VM 中运行的任何其他小程序。

提示

为什么要编写小程序代码？如果是由于规范原因。老师写的，请引用Why CS teachers should stop teaching Java applets .

基本上，小程序的开发一直很困难，最近变得更加困难。如果您显然缺乏经验(例如难以理解堆栈跟踪)，那么在您开发至少几个桌面应用程序之前，应该避免使用小程序。