NullPointerException: Compute launch button tooltip

[Mat]

Hello,

since recently, I frequently experience the following error:

An internal error occurred during: "Compute launch button tooltip".
java.lang.NullPointerException

There seem to be tickets already (#2821, #2828), but they have
status "Invalid" or "Fixed".

Further details:

Scala IDE for Eclipse 2.0.1.nightly-2_09-201203100537-099b3d7

Eclipse Version: 3.7.1
Build id: M20110909-1335

java.lang.NullPointerException
at
org.eclipse.jdt.internal.compiler.parser.TypeConverter.createTypeReference(TypeConverter.java:
126)
at
org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.convert(SourceTypeConverter.java:
230)
at
org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.convert(SourceTypeConverter.java:
530)
at org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.ajc
$privMethod
$scala_tools_eclipse_contribution_weaving_jdt_cfprovider_ClassFileProviderAspect
$org_eclipse_jdt_internal_compiler_parser_SourceTypeConverter
$convert(SourceTypeConverter.java:1)
at
scala.tools.eclipse.contribution.weaving.jdt.cfprovider.ClassFileProviderAspect.ajc
$around
$scala_tools_eclipse_contribution_weaving_jdt_cfprovider_ClassFileProviderAspect
$12$998f7f7a(ClassFileProviderAspect.aj:369)
at
org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.convert(SourceTypeConverter.java:
108)
at
org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.buildCompilationUnit(SourceTypeConverter.java:
94)
at
org.eclipse.jdt.internal.core.hierarchy.HierarchyResolver.resolve(HierarchyResolver.java:
671)
at
org.eclipse.jdt.internal.core.hierarchy.HierarchyResolver.resolve_aroundBody2(HierarchyResolver.java:
592)
at org.eclipse.jdt.internal.core.hierarchy.HierarchyResolver
$AjcClosure3.run(HierarchyResolver.java:1)
at
scala.tools.eclipse.contribution.weaving.jdt.cfprovider.ClassFileProviderAspect.ajc
$around
$scala_tools_eclipse_contribution_weaving_jdt_cfprovider_ClassFileProviderAspect
$8$2bb6fd97proceed(ClassFileProviderAspect.aj:1)
at
scala.tools.eclipse.contribution.weaving.jdt.cfprovider.ClassFileProviderAspect.ajc
$around
$scala_tools_eclipse_contribution_weaving_jdt_cfprovider_ClassFileProviderAspect
$8$2bb6fd97(ClassFileProviderAspect.aj:238)
at
org.eclipse.jdt.internal.core.hierarchy.HierarchyResolver.resolve(HierarchyResolver.java:
559)
at
org.eclipse.jdt.internal.core.hierarchy.HierarchyBuilder.buildSupertypes(HierarchyBuilder.java:
115)
at
org.eclipse.jdt.internal.core.hierarchy.IndexBasedHierarchyBuilder.build(IndexBasedHierarchyBuilder.java:
135)
at
org.eclipse.jdt.internal.core.hierarchy.TypeHierarchy.compute(TypeHierarchy.java:
300)
at
org.eclipse.jdt.internal.core.hierarchy.TypeHierarchy.refresh(TypeHierarchy.java:
1263)
at
org.eclipse.jdt.internal.core.CreateTypeHierarchyOperation.executeOperation(CreateTypeHierarchyOperation.java:
90)
at
org.eclipse.jdt.internal.core.JavaModelOperation.run(JavaModelOperation.java:
728)
at
org.eclipse.jdt.internal.core.JavaModelOperation.runOperation(JavaModelOperation.java:
788)
at
org.eclipse.jdt.internal.core.SourceType.newSupertypeHierarchy(SourceType.java:
726)
at
org.eclipse.jdt.internal.core.SourceType.newSupertypeHierarchy(SourceType.java:
678)
at
org.eclipse.jdt.internal.launching.JavaLaunchableTester.hasSuperclass(JavaLaunchableTester.java:
470)
at
org.eclipse.jdt.internal.launching.JavaLaunchableTester.test(JavaLaunchableTester.java:
613)
at org.eclipse.core.internal.expressions.Property.test(Property.java:
58)
at
org.eclipse.core.internal.expressions.TestExpression.evaluate(TestExpression.java:
99)
at
org.eclipse.core.internal.expressions.CompositeExpression.evaluateOr(CompositeExpression.java:
68)
at
org.eclipse.core.internal.expressions.OrExpression.evaluate(OrExpression.java:
21)
at
org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:
53)
at
org.eclipse.core.internal.expressions.AndExpression.evaluate(AndExpression.java:
29)
at
org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:
53)
at
org.eclipse.core.internal.expressions.IterateExpression.evaluate(IterateExpression.java:
150)
at
org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:
53)
at
org.eclipse.core.internal.expressions.WithExpression.evaluate(WithExpression.java:
72)
at
org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:
53)
at
org.eclipse.core.internal.expressions.EnablementExpression.evaluate(EnablementExpression.java:
53)
at
org.eclipse.debug.internal.ui.launchConfigurations.LaunchShortcutExtension.evalEnablementExpression(LaunchShortcutExtension.java:
287)
at
org.eclipse.debug.internal.ui.contextlaunching.LaunchingResourceManager.getShortcutsForSelection(LaunchingResourceManager.java:
456)
at
org.eclipse.debug.internal.ui.contextlaunching.LaunchingResourceManager.computeLabels(LaunchingResourceManager.java:
236)
at
org.eclipse.debug.internal.ui.contextlaunching.LaunchingResourceManager
$2.run(LaunchingResourceManager.java:138)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)