使用system.out.println打印包含int值的数组

Question

I am trying to display an array using System.out.println , but I constantly get an warning message when Eclipse is trying to run the code:

"An internal error has occured", and under "Details": -java.lang.NullPointerException

Here is the code:

import java.util.Arrays;

public class testerArray {
    public static void main(String[] args) {
        int [] test = {-1, -1, -1, -1};     
        System.out.println(java.util.Arrays.toString(test));
    }
}

I have searched many solutions on this site, but I must have become blind, because I can´t see what I do different from the examples used on the answers on this site. What do I do wrong?

Here is the stacktrace:

java.lang.NullPointerException
at org.eclipse.ui.part.PageBookView.showPageRec(PageBookView.java:1000)
atorg.eclipse.ui.internal.console.ConsoleView.showPageRec(ConsoleView.ava:171)
at org.eclipse.ui.part.PageBookView.partActivated(PageBookView.java:779)
at org.eclipse.ui.internal.console.ConsoleView.display(ConsoleView.java:531)
at org.eclipse.ui.internal.console.ConsoleManager$ShowConsoleViewJob.runInUIThread(ConsoleManager.java:313)
at org.eclipse.ui.progress.UIJob$1.run(UIJob.java:97)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:136)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3983)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3660)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1151)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:135)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:382)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:236)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.lang.NullPointerException
at org.eclipse.ui.part.PageBookView.showPageRec(PageBookView.java:1000)
at org.eclipse.ui.internal.console.ConsoleView.showPageRec(ConsoleView.java:171)
at org.eclipse.ui.part.PageBookView.partActivated(PageBookView.java:779)
at org.eclipse.ui.internal.console.ConsoleView.display(ConsoleView.java:531)
at org.eclipse.ui.internal.console.ConsoleManager$ShowConsoleViewJob.runInUIThread(ConsoleManager.java:313)
at org.eclipse.ui.progress.UIJob$1.run(UIJob.java:97)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:136)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3983)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3660)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1151)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:135)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:382)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:236)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
at org.eclipse.equinox.launcher.Main.run(Main.java:1465)sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
at org.eclipse.equinox.launcher.Main.run(Main.java:1465)

Answer 1

That looks more like an Eclipse problem than a code problem(in the stacktrace, you will see that the origin from the problem is in Eclipse classes). Why don't you try to run this file without Eclipse? http://www.cs.swarthmore.edu/~newhall/unixhelp/debuggingtips_Java.html#compiling

In that way,if it works, you will know that it is an Eclipse problem.