The hovering features, Open Declaration, Open Type Hierarchy and Open Call Hierarchy stopped working simutaneously on a specific project. On hovering it reported ClassCastException, while other operations reported InvocationTargetException.
This problem occured on a specific (Gradle) project. On other projects it worked correctly. Rebooting Eclipse and rebooting PC didn't work. Deleting then re-importing the project mostly didn't work, but randomly temporarily fixed it but after some editing operations the problem reoccured.

Eclipse version: 2023-09
JDK version: Java 17
====================================

Error information on hovering:

eclipse.buildId=4.29.0.20230907-1200
java.version=19.0.1
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

org.eclipse.jface.text
Error
Sun Oct 29 16:53:58 CST 2023
Unexpected runtime error while computing a text hover

java.lang.ClassCastException: class org.eclipse.jdt.internal.compiler.ast.LocalDeclaration cannot be cast to class org.eclipse.jdt.internal.compiler.ast.LambdaExpression (org.eclipse.jdt.internal.compiler.ast.LocalDeclaration and org.eclipse.jdt.internal.compiler.ast.LambdaExpression are in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @240ef200)
	at org.eclipse.jdt.internal.compiler.parser.Parser.consumeLambdaExpression(Parser.java:9132)
	at org.eclipse.jdt.internal.codeassist.select.SelectionParser.consumeLambdaExpression(SelectionParser.java:874)
	at org.eclipse.jdt.internal.compiler.parser.Parser.consumeRule(Parser.java:7927)
	at org.eclipse.jdt.internal.compiler.parser.Parser.parse(Parser.java:13145)
	at org.eclipse.jdt.internal.compiler.parser.Parser.parse(Parser.java:13400)
	at org.eclipse.jdt.internal.codeassist.select.SelectionParser.parse(SelectionParser.java:1665)
	at org.eclipse.jdt.internal.compiler.parser.Parser.parse(Parser.java:13357)
	at org.eclipse.jdt.internal.compiler.parser.Parser.dietParse(Parser.java:11743)
	at org.eclipse.jdt.internal.codeassist.select.SelectionParser.dietParse(SelectionParser.java:1489)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.select(SelectionEngine.java:994)
	at org.eclipse.jdt.internal.core.Openable.codeSelect(Openable.java:167)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:389)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:382)
	at org.eclipse.jdt.internal.ui.text.java.hover.AbstractJavaEditorTextHover.getJavaElementsAt(AbstractJavaEditorTextHover.java:121)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavadocHover.internalGetHoverInfo(JavadocHover.java:667)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavadocHover.getHoverInfo2(JavadocHover.java:663)
	at org.eclipse.jdt.internal.ui.text.java.hover.BestMatchHover.getHoverInfo2(BestMatchHover.java:163)
	at org.eclipse.jdt.internal.ui.text.java.hover.BestMatchHover.getHoverInfo2(BestMatchHover.java:130)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavaEditorTextHoverProxy.getHoverInfo2(JavaEditorTextHoverProxy.java:89)
	at org.eclipse.jface.text.TextViewerHoverManager$1.run(TextViewerHoverManager.java:155)

====================

Error opening declaration, type hierarchy and call hierarchy:

eclipse.buildId=4.29.0.20230907-1200
java.version=19.0.1
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

org.eclipse.jdt.ui
Error
Sun Oct 29 17:12:47 CST 2023
Internal Error

java.lang.reflect.InvocationTargetException
	at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:395)
	at org.eclipse.jface.dialogs.ProgressMonitorDialog.run(ProgressMonitorDialog.java:470)
	at org.eclipse.ui.internal.progress.ProgressMonitorJobsDialog.run(ProgressMonitorJobsDialog.java:230)
	at org.eclipse.ui.internal.progress.ProgressManager.lambda$26(ProgressManager.java:836)
	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:67)
	at org.eclipse.ui.internal.progress.ProgressManager.busyCursorWhile(ProgressManager.java:869)
	at org.eclipse.ui.internal.progress.ProgressManager.busyCursorWhile(ProgressManager.java:845)
	at org.eclipse.jdt.internal.ui.actions.SelectionConverter.performForkedCodeResolve(SelectionConverter.java:261)
	at org.eclipse.jdt.internal.ui.actions.SelectionConverter.codeResolveOrInputForked(SelectionConverter.java:124)
	at org.eclipse.jdt.internal.ui.callhierarchy.OpenCallHierarchyAction.run(OpenCallHierarchyAction.java:98)
	at org.eclipse.jdt.ui.actions.SelectionDispatchAction.dispatchRun(SelectionDispatchAction.java:278)
	at org.eclipse.jdt.ui.actions.SelectionDispatchAction.run(SelectionDispatchAction.java:252)
	at org.eclipse.jface.action.Action.runWithEvent(Action.java:474)
	at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:580)
	at org.eclipse.jface.action.ActionContributionItem.lambda$4(ActionContributionItem.java:414)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4274)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1066)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4072)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3660)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1155)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:342)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1046)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
	at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:645)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:342)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:552)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:171)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:152)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:136)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:402)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
	at java.base/java.lang.reflect.Method.invoke(Method.java:578)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:651)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:588)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1459)
Caused by: java.lang.ClassCastException: class org.eclipse.jdt.internal.compiler.ast.LocalDeclaration cannot be cast to class org.eclipse.jdt.internal.compiler.ast.LambdaExpression (org.eclipse.jdt.internal.compiler.ast.LocalDeclaration and org.eclipse.jdt.internal.compiler.ast.LambdaExpression are in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @240ef200)
	at org.eclipse.jdt.internal.compiler.parser.Parser.consumeLambdaExpression(Parser.java:9132)
	at org.eclipse.jdt.internal.codeassist.select.SelectionParser.consumeLambdaExpression(SelectionParser.java:874)
	at org.eclipse.jdt.internal.compiler.parser.Parser.consumeRule(Parser.java:7927)
	at org.eclipse.jdt.internal.compiler.parser.Parser.parse(Parser.java:13145)
	at org.eclipse.jdt.internal.compiler.parser.Parser.parse(Parser.java:13400)
	at org.eclipse.jdt.internal.codeassist.select.SelectionParser.parse(SelectionParser.java:1665)
	at org.eclipse.jdt.internal.compiler.parser.Parser.parse(Parser.java:13357)
	at org.eclipse.jdt.internal.compiler.parser.Parser.dietParse(Parser.java:11743)
	at org.eclipse.jdt.internal.codeassist.select.SelectionParser.dietParse(SelectionParser.java:1489)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.select(SelectionEngine.java:994)
	at org.eclipse.jdt.internal.core.Openable.codeSelect(Openable.java:167)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:389)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:382)
	at org.eclipse.jdt.internal.ui.actions.SelectionConverter.codeResolve(SelectionConverter.java:270)
	at org.eclipse.jdt.internal.ui.actions.SelectionConverter$1CodeResolveRunnable.run(SelectionConverter.java:254)
	at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:122)