IDEA2021.1 Error when opening CLS file

[gaoshan001]

java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask@157bd0ab[Not completed, task = java.util.concurrent.Executors$RunnableAdapter@76d68d15[Wrapped task = org.wso2.lsp4intellij.IntellijLanguageClient$$Lambda$1779/0x0000000101944440@6de1907]] rejected from java.util.concurrent.ThreadPoolExecutor@6d4deb4a[Shutting down, pool size = 1, active threads = 1, queued tasks = 1, completed tasks = 16] at java.base/java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2055) at java.base/java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:825) at java.base/java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1355) at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118) at java.base/java.util.concurrent.Executors$DelegatedExecutorService.submit(Executors.java:714) at org.wso2.lsp4intellij.utils.ApplicationUtils.pool(ApplicationUtils.java:52) at org.wso2.lsp4intellij.IntellijLanguageClient.editorOpened(IntellijLanguageClient.java:203) at org.wso2.lsp4intellij.listeners.LSPEditorListener.editorCreated(LSPEditorListener.java:35) at jdk.internal.reflect.GeneratedMethodAccessor624.invoke(Unknown Source) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at com.intellij.util.EventDispatcher.dispatchVoidMethod(EventDispatcher.java:123) at com.intellij.util.EventDispatcher.lambda$createMulticaster$1(EventDispatcher.java:86) at com.sun.proxy.$Proxy88.editorCreated(Unknown Source) at com.intellij.openapi.editor.impl.EditorFactoryImpl.createEditor(EditorFactoryImpl.java:203) at com.intellij.openapi.editor.impl.EditorFactoryImpl.createEditor(EditorFactoryImpl.java:158) at com.intellij.openapi.fileEditor.impl.text.TextEditorComponent.createEditor(TextEditorComponent.java:133) at com.intellij.openapi.fileEditor.impl.text.TextEditorComponent.(TextEditorComponent.java:79) at com.intellij.openapi.fileEditor.impl.text.PsiAwareTextEditorImpl$PsiAwareTextEditorComponent.(PsiAwareTextEditorImpl.java:107) at com.intellij.openapi.fileEditor.impl.text.PsiAwareTextEditorImpl.createEditorComponent(PsiAwareTextEditorImpl.java:85) at com.intellij.openapi.fileEditor.impl.text.TextEditorImpl.(TextEditorImpl.java:52) at com.intellij.openapi.fileEditor.impl.text.PsiAwareTextEditorImpl.(PsiAwareTextEditorImpl.java:36) at com.intellij.openapi.fileEditor.impl.text.PsiAwareTextEditorProvider.createEditor(PsiAwareTextEditorProvider.java:31) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.openFileImpl4Edt(FileEditorManagerImpl.java:983) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.lambda$openFileImpl4$17(FileEditorManagerImpl.java:954) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.runBulkTabChange(FileEditorManagerImpl.java:1766) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.lambda$openFileImpl4$18(FileEditorManagerImpl.java:953) at com.intellij.openapi.application.impl.ApplicationImpl.invokeAndWait(ApplicationImpl.java:415) at com.intellij.openapi.application.impl.ApplicationImpl.invokeAndWait(ApplicationImpl.java:433) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.openFileImpl4(FileEditorManagerImpl.java:952) at com.jetbrains.rdserver.editors.BackendServerFileEditorManager.openFileImpl4(BackendServerFileEditorManager.kt:80) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.openFileImpl3(FileEditorManagerImpl.java:898) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.lambda$openFileImpl2$14(FileEditorManagerImpl.java:879) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:207) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:172) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:162) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:148) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.openFileImpl2(FileEditorManagerImpl.java:879) at com.intellij.openapi.fileEditor.impl.FileEditorManagerImpl.openFileWithProviders(FileEditorManagerImpl.java:765) at com.intellij.openapi.fileEditor.ex.FileEditorManagerEx.openFile(FileEditorManagerEx.java:133) at com.intellij.codeInsight.navigation.NavigationUtil.activatePsiElementIfOpen(NavigationUtil.java:202) at com.intellij.codeInsight.navigation.NavigationUtil.lambda$openFileWithPsiElement$2(NavigationUtil.java:172) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:216) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:172) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:162) at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:148) at com.intellij.codeInsight.navigation.NavigationUtil.openFileWithPsiElement(NavigationUtil.java:171) at com.intellij.ide.projectView.impl.nodes.AbstractPsiBasedNode.navigate(AbstractPsiBasedNode.java:235) at com.intellij.ide.projectView.impl.nodes.AbstractPsiBasedNode.navigate(AbstractPsiBasedNode.java:245) at com.intellij.ide.projectView.impl.nodes.PsiFileNode.navigate(PsiFileNode.java:116) at com.intellij.util.OpenSourceUtil.navigateToSource(OpenSourceUtil.java:119) at com.intellij.util.OpenSourceUtil.navigate(OpenSourceUtil.java:74) at com.intellij.util.OpenSourceUtil.navigate(OpenSourceUtil.java:58) at com.intellij.util.OpenSourceUtil.navigate(OpenSourceUtil.java:51) at com.intellij.util.OpenSourceUtil.openSourcesFrom(OpenSourceUtil.java:19) at com.intellij.util.EditSourceOnDoubleClickHandler$TreeMouseListener.processDoubleClick(EditSourceOnDoubleClickHandler.java:166) at com.intellij.util.EditSourceOnDoubleClickHandler$TreeMouseListener.onDoubleClick(EditSourceOnDoubleClickHandler.java:160) at com.intellij.ui.DoubleClickListener.onClick(DoubleClickListener.java:30) at com.intellij.ui.ClickListener$1.mouseReleased(ClickListener.java:59) at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:298) at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297) at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297) at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297) at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297) at java.desktop/java.awt.Component.processMouseEvent(Component.java:6652) at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3345) at com.intellij.ui.treeStructure.Tree.processMouseEvent(Tree.java:392) at com.intellij.ide.dnd.aware.DnDAwareTree.processMouseEvent(DnDAwareTree.java:45) at java.desktop/java.awt.Component.processEvent(Component.java:6417) at java.desktop/java.awt.Container.processEvent(Container.java:2263) at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5027) at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321) at java.desktop/java.awt.Component.dispatchEvent(Component.java:4859) at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918) at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547) at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488) at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307) at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2784) at java.desktop/java.awt.Component.dispatchEvent(Component.java:4859) at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:778) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:727) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85) at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95) at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:751) at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:749) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85) at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:748) at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:969) at com.intellij.ide.IdeEventQueue.dispatchMouseEvent(IdeEventQueue.java:906) at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:836) at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$8(IdeEventQueue.java:449) at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:808) at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$9(IdeEventQueue.java:448) at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:781) at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:502) at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203) at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124) at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109) at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)