JDK-9不允许我使用String："java.lang.String是模棱两可的“？

Question

一周前，我所有的项目都在正常工作，但是当我将Eclipse升级到氧气版本并安装JDK-9时，事情变得很奇怪。当我尝试使用String时，经过一段时间(更像每次保存项目)，编译器会为我的项目中的每个字符串抛出一个错误。

字符串类型被识别为歧义类。

“类型java.lang.String是不明确的”

因此，我尝试导入java.lang.String以查看它是否修复了错误：

进口后

“包java.lang可以从多个模块访问: java.base，java.base”

惊喜吧！

它没有：

我试过在谷歌上搜索这些信息，但是我什么也没找到.

但是，在JDK 8中运行的代码似乎正常运行，请检查它：

改为JDK 8 (1.8.0_72)

​

(代码在应用程序之前没有显示任何错误，因为我已经应用了，并再次为屏幕快照打开编译器首选项)

控制台错误：

错误:在类me.mateusakino.ypul.yPuLTester中找不到主方法，请将主方法定义为： public static void main(String[] args)或JavaFX应用程序类必须扩展javafx.application.Application

编辑1-主类

​

​

编辑5-编辑4上错误的堆栈跟踪(工作区/.元数据/..log)

!SESSION 2017-10-13 13:11:39.551 -----------------------------------------------
eclipse.buildId=4.7.1.M20171009-0410
java.version=9
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.java.product
Command-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.java.product

This is a continuation of log file C:\Users\Home\Desktop\Developer Folders\Java\Oxygen Workspace\.metadata\.bak_0.log
Created Time: 2017-10-13 13:43:14.245

!ENTRY org.eclipse.core.resources 4 75 2017-10-13 13:43:14.245
!MESSAGE Errors occurred during the build.
!SUBENTRY 1 org.eclipse.jdt.core 4 75 2017-10-13 13:43:14.245
!MESSAGE Errors running builder 'Java Builder' on project 'yPuL'.
!STACK 0
java.lang.NullPointerException
    at org.eclipse.jdt.internal.compiler.lookup.ModuleBinding$UnNamedModule.canAccess(ModuleBinding.java:71)
    at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getTypeOrPackage(PackageBinding.java:230)
    at org.eclipse.jdt.internal.compiler.lookup.Scope.getPackage(Scope.java:2922)
    at org.eclipse.jdt.internal.compiler.ast.QualifiedTypeReference.getTypeBinding(QualifiedTypeReference.java:108)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.getTypeBinding(ArrayQualifiedTypeReference.java:93)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.internalResolveType(TypeReference.java:495)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.internalResolveType(ArrayQualifiedTypeReference.java:107)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:586)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:582)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesWithSuspendedTempErrorHandlingPolicy(SourceTypeBinding.java:1932)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesFor(SourceTypeBinding.java:1835)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.methods(SourceTypeBinding.java:1525)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.internalFaultInTypeForFieldsAndMethods(SourceTypeBinding.java:907)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.faultInTypesForFieldsAndMethods(SourceTypeBinding.java:902)
    at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.faultInTypes(CompilationUnitScope.java:514)
    at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:882)
    at org.eclipse.jdt.internal.compiler.ProcessTaskManager.run(ProcessTaskManager.java:141)
    at java.base/java.lang.Thread.run(Thread.java:844)

!ENTRY org.eclipse.core.resources 4 2 2017-10-13 13:43:24.691
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.core.resources".
!STACK 0
java.lang.NullPointerException

!ENTRY org.eclipse.core.resources 4 75 2017-10-13 13:43:24.695
!MESSAGE Errors occurred during the build.
!SUBENTRY 1 org.eclipse.jdt.core 4 75 2017-10-13 13:43:24.695
!MESSAGE Errors running builder 'Java Builder' on project 'yPuL'.
!STACK 0
java.lang.NullPointerException

!ENTRY org.eclipse.core.resources 4 2 2017-10-13 13:43:39.104
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.core.resources".
!STACK 0
java.lang.NullPointerException

!ENTRY org.eclipse.core.resources 4 75 2017-10-13 13:43:39.110
!MESSAGE Errors occurred during the build.
!SUBENTRY 1 org.eclipse.jdt.core 4 75 2017-10-13 13:43:39.110
!MESSAGE Errors running builder 'Java Builder' on project 'yPuL'.
!STACK 0
java.lang.NullPointerException

!ENTRY org.eclipse.core.resources 4 2 2017-10-13 13:44:37.810
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.core.resources".
!STACK 0
java.lang.NullPointerException
    at org.eclipse.jdt.internal.compiler.lookup.ModuleBinding$UnNamedModule.canAccess(ModuleBinding.java:71)
    at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getTypeOrPackage(PackageBinding.java:230)
    at org.eclipse.jdt.internal.compiler.lookup.Scope.getPackage(Scope.java:2922)
    at org.eclipse.jdt.internal.compiler.ast.QualifiedTypeReference.getTypeBinding(QualifiedTypeReference.java:108)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.getTypeBinding(ArrayQualifiedTypeReference.java:93)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.internalResolveType(TypeReference.java:495)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.internalResolveType(ArrayQualifiedTypeReference.java:107)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:586)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:582)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesWithSuspendedTempErrorHandlingPolicy(SourceTypeBinding.java:1932)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesFor(SourceTypeBinding.java:1835)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.methods(SourceTypeBinding.java:1525)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.internalFaultInTypeForFieldsAndMethods(SourceTypeBinding.java:907)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.faultInTypesForFieldsAndMethods(SourceTypeBinding.java:902)
    at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.faultInTypes(CompilationUnitScope.java:514)
    at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:882)
    at org.eclipse.jdt.internal.compiler.ProcessTaskManager.run(ProcessTaskManager.java:141)
    at java.base/java.lang.Thread.run(Thread.java:844)

!ENTRY org.eclipse.core.resources 4 75 2017-10-13 13:44:37.814
!MESSAGE Errors occurred during the build.
!SUBENTRY 1 org.eclipse.jdt.core 4 75 2017-10-13 13:44:37.814
!MESSAGE Errors running builder 'Java Builder' on project 'yPuL'.
!STACK 0
java.lang.NullPointerException
    at org.eclipse.jdt.internal.compiler.lookup.ModuleBinding$UnNamedModule.canAccess(ModuleBinding.java:71)
    at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getTypeOrPackage(PackageBinding.java:230)
    at org.eclipse.jdt.internal.compiler.lookup.Scope.getPackage(Scope.java:2922)
    at org.eclipse.jdt.internal.compiler.ast.QualifiedTypeReference.getTypeBinding(QualifiedTypeReference.java:108)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.getTypeBinding(ArrayQualifiedTypeReference.java:93)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.internalResolveType(TypeReference.java:495)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.internalResolveType(ArrayQualifiedTypeReference.java:107)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:586)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:582)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesWithSuspendedTempErrorHandlingPolicy(SourceTypeBinding.java:1932)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesFor(SourceTypeBinding.java:1835)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.methods(SourceTypeBinding.java:1525)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.internalFaultInTypeForFieldsAndMethods(SourceTypeBinding.java:907)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.faultInTypesForFieldsAndMethods(SourceTypeBinding.java:902)
    at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.faultInTypes(CompilationUnitScope.java:514)
    at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:882)
    at org.eclipse.jdt.internal.compiler.ProcessTaskManager.run(ProcessTaskManager.java:141)
    at java.base/java.lang.Thread.run(Thread.java:844)

!ENTRY org.eclipse.core.resources 4 2 2017-10-13 13:44:53.701
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.core.resources".
!STACK 0
java.lang.NullPointerException
    at org.eclipse.jdt.internal.compiler.lookup.ModuleBinding$UnNamedModule.canAccess(ModuleBinding.java:71)
    at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getTypeOrPackage(PackageBinding.java:230)
    at org.eclipse.jdt.internal.compiler.lookup.Scope.getPackage(Scope.java:2922)
    at org.eclipse.jdt.internal.compiler.ast.QualifiedTypeReference.getTypeBinding(QualifiedTypeReference.java:108)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.getTypeBinding(ArrayQualifiedTypeReference.java:93)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.internalResolveType(TypeReference.java:495)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.internalResolveType(ArrayQualifiedTypeReference.java:107)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:586)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:582)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesWithSuspendedTempErrorHandlingPolicy(SourceTypeBinding.java:1932)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesFor(SourceTypeBinding.java:1835)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.methods(SourceTypeBinding.java:1525)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.internalFaultInTypeForFieldsAndMethods(SourceTypeBinding.java:907)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.faultInTypesForFieldsAndMethods(SourceTypeBinding.java:902)
    at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.faultInTypes(CompilationUnitScope.java:514)
    at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:882)
    at org.eclipse.jdt.internal.compiler.ProcessTaskManager.run(ProcessTaskManager.java:141)
    at java.base/java.lang.Thread.run(Thread.java:844)

!ENTRY org.eclipse.core.resources 4 75 2017-10-13 13:44:53.706
!MESSAGE Errors occurred during the build.
!SUBENTRY 1 org.eclipse.jdt.core 4 75 2017-10-13 13:44:53.706
!MESSAGE Errors running builder 'Java Builder' on project 'yPuL'.
!STACK 0
java.lang.NullPointerException
    at org.eclipse.jdt.internal.compiler.lookup.ModuleBinding$UnNamedModule.canAccess(ModuleBinding.java:71)
    at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getTypeOrPackage(PackageBinding.java:230)
    at org.eclipse.jdt.internal.compiler.lookup.Scope.getPackage(Scope.java:2922)
    at org.eclipse.jdt.internal.compiler.ast.QualifiedTypeReference.getTypeBinding(QualifiedTypeReference.java:108)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.getTypeBinding(ArrayQualifiedTypeReference.java:93)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.internalResolveType(TypeReference.java:495)
    at org.eclipse.jdt.internal.compiler.ast.ArrayQualifiedTypeReference.internalResolveType(ArrayQualifiedTypeReference.java:107)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:586)
    at org.eclipse.jdt.internal.compiler.ast.TypeReference.resolveType(TypeReference.java:582)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesWithSuspendedTempErrorHandlingPolicy(SourceTypeBinding.java:1932)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.resolveTypesFor(SourceTypeBinding.java:1835)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.methods(SourceTypeBinding.java:1525)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.internalFaultInTypeForFieldsAndMethods(SourceTypeBinding.java:907)
    at org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.faultInTypesForFieldsAndMethods(SourceTypeBinding.java:902)
    at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.faultInTypes(CompilationUnitScope.java:514)
    at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:882)
    at org.eclipse.jdt.internal.compiler.ProcessTaskManager.run(ProcessTaskManager.java:141)
    at java.base/java.lang.Thread.run(Thread.java:844)
!SESSION 2017-10-13 13:46:42.392 -----------------------------------------------
eclipse.buildId=4.7.1.M20171009-0410
java.version=9
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.java.product
Command-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.java.product

!ENTRY org.eclipse.jface 2 0 2017-10-13 13:46:49.852
!MESSAGE Keybinding conflicts occurred.  They may interfere with normal accelerator operation.
!SUBENTRY 1 org.eclipse.jface 2 0 2017-10-13 13:46:49.852
!MESSAGE A conflict occurred for CTRL+TAB:
Binding(CTRL+TAB,
    ParameterizedCommand(Command(org.eclipse.ui.window.nextEditor,Next Editor,
        Switch to the next editor,
        Category(org.eclipse.ui.category.window,Window,null,true),
        org.eclipse.ui.internal.WorkbenchHandlerServiceHandler@5e8359da,
        ,,true),null),
    org.eclipse.ui.defaultAcceleratorConfiguration,
    org.eclipse.ui.contexts.window,,,system)
Binding(CTRL+TAB,
    ParameterizedCommand(Command(org.eclipse.ui.window.nextEditor,Next Editor,
        Switch to the next editor,
        Category(org.eclipse.ui.category.window,Window,null,true),
        org.eclipse.ui.internal.WorkbenchHandlerServiceHandler@5e8359da,
        ,,true),null),
    org.eclipse.ui.defaultAcceleratorConfiguration,
    org.eclipse.ui.contexts.window,,,system)
!SUBENTRY 1 org.eclipse.jface 2 0 2017-10-13 13:46:49.852
!MESSAGE A conflict occurred for CTRL+SHIFT+TAB:
Binding(CTRL+SHIFT+TAB,
    ParameterizedCommand(Command(org.eclipse.ui.window.previousEditor,Previous Editor,
        Switch to the previous editor,
        Category(org.eclipse.ui.category.window,Window,null,true),
        org.eclipse.ui.internal.WorkbenchHandlerServiceHandler@36b6802f,
        ,,true),null),
    org.eclipse.ui.defaultAcceleratorConfiguration,
    org.eclipse.ui.contexts.window,,,system)
Binding(CTRL+SHIFT+TAB,
    ParameterizedCommand(Command(org.eclipse.ui.window.previousEditor,Previous Editor,
        Switch to the previous editor,
        Category(org.eclipse.ui.category.window,Window,null,true),
        org.eclipse.ui.internal.WorkbenchHandlerServiceHandler@36b6802f,
        ,,true),null),
    org.eclipse.ui.defaultAcceleratorConfiguration,
    org.eclipse.ui.contexts.window,,,system)

!ENTRY com.vaadin.designer2 1 0 2017-10-13 13:47:00.882
!MESSAGE Schedule fetching all notifications

!ENTRY com.vaadin.designer2 1 0 2017-10-13 13:47:02.845
!MESSAGE Parse notifications

!ENTRY com.vaadin.designer2 1 0 2017-10-13 13:47:03.278
!MESSAGE Requesting user info (notification settings URL)

!ENTRY com.vaadin.designer2 1 0 2017-10-13 13:47:04.704
!MESSAGE HTTP Response code :200

!ENTRY org.eclipse.egit.ui 2 0 2017-10-13 13:47:06.014
!MESSAGE Warning: The environment variable HOME is not set. The following directory will be used to store the Git
user global configuration and to define the default location to store repositories: 'C:\Users\Home'. If this is
not correct please set the HOME environment variable and restart Eclipse. Otherwise Git for Windows and
EGit might behave differently since they see different configuration options.
This warning can be switched off on the Team > Git > Confirmations and Warnings preference page.

!ENTRY org.eclipse.dltk.core 4 0 2017-10-13 13:47:07.129
!MESSAGE Unable to find any indexer

!ENTRY org.apache.ivyde.eclipse 1 0 2017-10-13 13:48:10.554
!MESSAGE starting IvyDE plugin

!ENTRY org.apache.ivyde.eclipse 1 0 2017-10-13 13:48:10.571
!MESSAGE IvyDE plugin started

!ENTRY org.eclipse.ui 2 2 2017-10-13 13:48:12.395
!MESSAGE Invalid property category path: org.eclipse.cdt.managedbuilder.ui.properties.Page_head_build (bundle: org.eclipse.cdt.ui, propertyPage: org.eclipse.cdt.managedbuilder.ui.properties.BuildLogPreferencePage)

!ENTRY org.eclipse.jface 4 2 2017-10-13 13:48:45.611
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.jface".
!STACK 0
java.lang.IllegalArgumentException
    at org.eclipse.core.resources.ProjectScope.<init>(ProjectScope.java:58)
    at com.vaadin.designer2.eclipse.preferences.VisualDesignerPreferences.getProjectPreferences(VisualDesignerPreferences.java:680)
    at com.vaadin.designer2.eclipse.preferences.VisualDesignerPreferences.getDefaultDesigner(VisualDesignerPreferences.java:245)
    at com.vaadin.designer2.eclipse.preferences.DesignerProjectPreferencePage.createDesignerSelection(DesignerProjectPreferencePage.java:179)
    at com.vaadin.designer2.eclipse.preferences.DesignerProjectPreferencePage.createContents(DesignerProjectPreferencePage.java:109)
    at org.eclipse.jface.preference.PreferencePage.createControl(PreferencePage.java:241)
    at org.eclipse.jface.preference.PreferenceDialog.createPageControl(PreferenceDialog.java:1426)
    at org.eclipse.jface.preference.PreferenceDialog$8.run(PreferenceDialog.java:1193)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:44)
    at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:173)
    at org.eclipse.jface.preference.PreferenceDialog.showPage(PreferenceDialog.java:1185)
    at org.eclipse.ui.internal.dialogs.FilteredPreferenceDialog.showPage(FilteredPreferenceDialog.java:591)
    at org.eclipse.jface.preference.PreferenceDialog$5.lambda$0(PreferenceDialog.java:657)
    at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
    at org.eclipse.jface.preference.PreferenceDialog$5.selectionChanged(PreferenceDialog.java:654)
    at org.eclipse.jface.viewers.StructuredViewer$3.run(StructuredViewer.java:872)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
    at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:44)
    at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:173)
    at org.eclipse.jface.viewers.StructuredViewer.firePostSelectionChanged(StructuredViewer.java:869)
    at org.eclipse.jface.viewers.StructuredViewer.handlePostSelect(StructuredViewer.java:1238)
    at org.eclipse.jface.viewers.StructuredViewer.lambda$0(StructuredViewer.java:1261)
    at org.eclipse.swt.events.SelectionListener$1.widgetSelected(SelectionListener.java:81)
    at org.eclipse.jface.util.OpenStrategy.firePostSelectionEvent(OpenStrategy.java:261)
    at org.eclipse.jface.util.OpenStrategy.access$5(OpenStrategy.java:256)
    at org.eclipse.jface.util.OpenStrategy$1.lambda$1(OpenStrategy.java:426)
    at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:37)
    at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:182)
    at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4213)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3820)
    at org.eclipse.jface.window.Window.runEventLoop(Window.java:818)
    at org.eclipse.jface.window.Window.open(Window.java:794)
    at org.eclipse.ui.dialogs.PropertyDialogAction.run(PropertyDialogAction.java:157)
    at org.eclipse.jface.action.Action.runWithEvent(Action.java:473)
    at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:565)
    at org.eclipse.jface.action.ActionContributionItem.lambda$4(ActionContributionItem.java:397)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:86)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4428)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1079)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4238)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3817)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1039)
    at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:153)
    at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:680)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:594)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:151)
    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:388)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:653)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:590)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1499)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1472)

编辑7：

我可以在另一个工作区(临时工作区)中再生产它，下面是从@howlger询问的.classpath文件：

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
    <classpathentry kind="src" path="src"/>
    <classpathentry kind="output" path="bin"/>
</classpath>

编辑8- Eclipse报告(由豪尔格要求)：

bug.cgi?id=526020

详细信息：

• 操作系统: Windows 10家庭(64位)
• JDK 9.0
• 初始Eclipse:氧气释放(4.7.0)构建id: 20170620-1800
• 当前Eclipse: Oxygen.1a版本(4.7.1a)构建id: 20171005-1200
• 编辑4:项目设置：
  • 参考图书馆：jRegex
  • 编码: UTF-8
  • 编译器设置
  • 执行环境

​

• 编辑4: Java9版本:构建9+181
• 编辑4: Java HotSpot(TM) 64位服务器VM (构建9+181，混合模式)
• 编辑6: 所有Eclipse的插件
• 如果需要任何其他信息，请在评论部分.

我试过的是：

• 重新启动IDE
• 搜索Java /Completion中是否有多个字符串(只有一个字符串，java.lang的)。
• 检查了JRE中的多个java.base包(只有一个来自jrt-fs.jar)。
• 编辑2：通过eclipse.ini添加模块
• 编辑2：将eclipse更新为版本: 4.7.1a (这篇文章里已经有太多的图片了)
• 编辑3：在项目和/或Eclipse (图像链接)中检查双JDK
• 编辑4：重新构建java索引(没有工作)，启用New Java index并重新构建:工作了大约3分钟，但随后出现了此错误，错误再次出现：java.lang.ClassCastException
• 编辑4：从默认库中删除JDK 9并再次添加它，这与上面的情况相同，但这次它将错误：java.lang.NullPointerException抛出到工作区，即使在重新启动IDE之后，字符串错误仍在发生.(顺便说一句，这个警告出现在package关键字中，不确定它以前是否已经在这里.)

Answer 1

在显示所有安装的Eclipse插件的屏幕截图中，我看到了一些非常可疑的东西:您安装了两个相互冲突的特性：

• Eclipse Java开发工具-3.13.1.v20171009-0.- good
• Eclipse (Java开发工具)补丁与Java 9支持(测试版)氧气开发流-1.1.v20170826-05.-不好

根据我对Eclipse中的修补程序特性的理解，第二个(旧的)特性可能会覆盖以前(较新的)特性的插件。这意味着，在更新到Oxygen.1a (支持Java 9的官方版本)之后，您仍然有效地运行了一个更早几周的beta版本。

要进行双重检查，您可以切换到对话框的插件选项卡，并搜索"jdt“。

这个观察可以很容易地解释，为什么您仍然受到bug的影响，而这些bug在发布之前就已经修复过了。

uninstalling 解决方案：--请尝试修补功能(并返回配置

编辑：在编译器设置中可以看到更多的证据，遵从性"9 (BETA)“清楚地表明您没有运行JDT的发布版本。

Answer 2

对于Java 9的支持，您需要以下两种方法：

1. EclipseOxygen.1a，可从https://www.eclipse.org/downloads/eclipse-packages/获得 或
2. 根据9的说法，用Java 9支持手动配置预Oxygen.1a Eclipse

选项1显然更简单，只要您能够控制安装和使用哪个版本的Eclipse。

Answer 3

对我来说，通过将项目从Eclipse中删除(并从磁盘中删除)解决了这个问题。然后再克隆和创建项目，解决了问题。