I had to download eclipse for a school assignment in order to create a GUI that check the type of the triangle. I installed all the needed packages from the General Purpose Tools in order to use Swing for building a GUI. After that I go to my project --> right click --> New --> Other --> Swing Designer --> JFrame. Writing code manually to create a GUI works but when I switch to the Design tab, I get this error: Unable to load *.wbp-component.xml description. For component javax.swing.JFrame. Here is my stack trace:
org.eclipse.wb.internal.core.utils.exception.DesignerException: 502 (Unable to load *.wbp-component.xml description.). javax.swing.JFrame at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription0(ComponentDescriptionHelper.java:442) at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription0(ComponentDescriptionHelper.java:289) at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription(ComponentDescriptionHelper.java:258) at org.eclipse.wb.internal.core.model.JavaInfoUtils.createJavaInfo(JavaInfoUtils.java:387) at org.eclipse.wb.internal.swing.parser.ParseFactory.getRootContext(ParseFactory.java:128) at org.eclipse.wb.internal.core.parser.JavaInfoParser.prepareParseContext(JavaInfoParser.java:1182) at org.eclipse.wb.internal.core.parser.JavaInfoParser.parse(JavaInfoParser.java:242) at org.eclipse.wb.internal.core.parser.JavaInfoParser.access$9(JavaInfoParser.java:238) at org.eclipse.wb.internal.core.parser.JavaInfoParser$1.runObject(JavaInfoParser.java:153) at org.eclipse.wb.internal.core.parser.JavaInfoParser$1.runObject(JavaInfoParser.java:1) at org.eclipse.wb.internal.core.utils.execution.ExecutionUtils.runDesignTime(ExecutionUtils.java:159) at org.eclipse.wb.internal.core.parser.JavaInfoParser.parse(JavaInfoParser.java:151) at org.eclipse.wb.internal.core.editor.DesignPage.internal_refreshGEF(DesignPage.java:534) at org.eclipse.wb.internal.core.editor.DesignPage.access$9(DesignPage.java:522) at org.eclipse.wb.internal.core.editor.DesignPage$8$1.run(DesignPage.java:449) at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:236) at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:133) at org.eclipse.swt.widgets.Display.syncExec(Display.java:4770) at org.eclipse.wb.internal.core.editor.DesignPage$8.run(DesignPage.java:446) at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:434) at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:352) at org.eclipse.jface.dialogs.ProgressMonitorDialog.run(ProgressMonitorDialog.java:468) at org.eclipse.wb.internal.core.editor.DesignPage.internal_refreshGEF_withProgress(DesignPage.java:465) at org.eclipse.wb.internal.core.editor.DesignPage.internal_refreshGEF(DesignPage.java:415) at org.eclipse.wb.internal.core.editor.UndoManager.refreshDesignerEditor(UndoManager.java:381) at org.eclipse.wb.internal.core.editor.DesignPage.refreshGEF(DesignPage.java:392) at org.eclipse.wb.internal.core.editor.actions.RefreshAction.run(RefreshAction.java:46) at org.eclipse.wb.internal.core.editor.actions.DesignPageAction.run(DesignPageAction.java:34) at org.eclipse.wb.internal.core.editor.errors.JavaExceptionComposite.doRefresh(JavaExceptionComposite.java:87) at org.eclipse.wb.internal.core.editor.errors.ExceptionComposite$3.widgetSelected(ExceptionComposite.java:129) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:252) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89) at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4237) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1060) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4054) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3626) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1041) at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155) at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:644) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:551) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:156) 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:401) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:568) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:659) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:596) at org.eclipse.equinox.launcher.Main.run(Main.java:1467) Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make protected java.lang.String javax.swing.JFrame.paramString() accessible: module java.desktop does not "opens javax.swing" to unnamed module @4dafea3f at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354) at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297) at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:199) at java.base/java.lang.reflect.Method.setAccessible(Method.java:193) at org.eclipse.wb.internal.core.utils.reflect.ReflectionUtils.appendPropertyComponents(ReflectionUtils.java:1560) at org.eclipse.wb.internal.core.utils.reflect.ReflectionUtils.getPropertyDescriptors(ReflectionUtils.java:1469) at org.eclipse.wb.internal.core.model.description.rules.StandardBeanPropertiesRule.begin(StandardBeanPropertiesRule.java:47) at org.apache.commons.digester.Digester.startElement(Digester.java:1563) at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:518) at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:183) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1387) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2726) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:542) at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:889) at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:825) at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141) at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1224) at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:637) at org.apache.commons.digester.Digester.parse(Digester.java:1887) at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription0(ComponentDescriptionHelper.java:389) ... 56 more
Full context stack trace: org.eclipse.wb.internal.core.utils.exception.DesignerException: 502 (Unable to load *.wbp-component.xml description.). javax.swing.JFrame at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription0(ComponentDescriptionHelper.java:442) at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription0(ComponentDescriptionHelper.java:289) at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription(ComponentDescriptionHelper.java:258) at org.eclipse.wb.internal.core.model.JavaInfoUtils.createJavaInfo(JavaInfoUtils.java:387) at org.eclipse.wb.internal.swing.parser.ParseFactory.getRootContext(ParseFactory.java:128) at org.eclipse.wb.internal.core.parser.JavaInfoParser.prepareParseContext(JavaInfoParser.java:1182) at org.eclipse.wb.internal.core.parser.JavaInfoParser.parse(JavaInfoParser.java:242) at org.eclipse.wb.internal.core.parser.JavaInfoParser.access$9(JavaInfoParser.java:238) at org.eclipse.wb.internal.core.parser.JavaInfoParser$1.runObject(JavaInfoParser.java:153) at org.eclipse.wb.internal.core.parser.JavaInfoParser$1.runObject(JavaInfoParser.java:1) at org.eclipse.wb.internal.core.utils.execution.ExecutionUtils.runDesignTime(ExecutionUtils.java:159) at org.eclipse.wb.internal.core.parser.JavaInfoParser.parse(JavaInfoParser.java:151) at org.eclipse.wb.internal.core.editor.DesignPage.internal_refreshGEF(DesignPage.java:534) at org.eclipse.wb.internal.core.editor.DesignPage.access$9(DesignPage.java:522) at org.eclipse.wb.internal.core.editor.DesignPage$8$1.run(DesignPage.java:449) at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:236) at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:133) at org.eclipse.swt.widgets.Display.syncExec(Display.java:4770) at org.eclipse.wb.internal.core.editor.DesignPage$8.run(DesignPage.java:446) at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:434) at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:352) at org.eclipse.jface.dialogs.ProgressMonitorDialog.run(ProgressMonitorDialog.java:468) at org.eclipse.wb.internal.core.editor.DesignPage.internal_refreshGEF_withProgress(DesignPage.java:465) at org.eclipse.wb.internal.core.editor.DesignPage.internal_refreshGEF(DesignPage.java:415) at org.eclipse.wb.internal.core.editor.UndoManager.refreshDesignerEditor(UndoManager.java:381) at org.eclipse.wb.internal.core.editor.DesignPage.refreshGEF(DesignPage.java:392) at org.eclipse.wb.internal.core.editor.actions.RefreshAction.run(RefreshAction.java:46) at org.eclipse.wb.internal.core.editor.actions.DesignPageAction.run(DesignPageAction.java:34) at org.eclipse.wb.internal.core.editor.errors.JavaExceptionComposite.doRefresh(JavaExceptionComposite.java:87) at org.eclipse.wb.internal.core.editor.errors.ExceptionComposite$3.widgetSelected(ExceptionComposite.java:129) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:252) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89) at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4237) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1060) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4054) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3626) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1041) at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155) at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:644) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:551) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:156) 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:401) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:568) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:659) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:596) at org.eclipse.equinox.launcher.Main.run(Main.java:1467) Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make protected java.lang.String javax.swing.JFrame.paramString() accessible: module java.desktop does not "opens javax.swing" to unnamed module @4dafea3f at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354) at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297) at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:199) at java.base/java.lang.reflect.Method.setAccessible(Method.java:193) at org.eclipse.wb.internal.core.utils.reflect.ReflectionUtils.appendPropertyComponents(ReflectionUtils.java:1560) at org.eclipse.wb.internal.core.utils.reflect.ReflectionUtils.getPropertyDescriptors(ReflectionUtils.java:1469) at org.eclipse.wb.internal.core.model.description.rules.StandardBeanPropertiesRule.begin(StandardBeanPropertiesRule.java:47) at org.apache.commons.digester.Digester.startElement(Digester.java:1563) at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:518) at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:183) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1387) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2726) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605) at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:542) at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:889) at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:825) at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141) at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1224) at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:637) at org.apache.commons.digester.Digester.parse(Digester.java:1887) at org.eclipse.wb.internal.core.model.description.helpers.ComponentDescriptionHelper.getDescription0(ComponentDescriptionHelper.java:389) ... 56 more