Changing of virtually in file in the Ticket Monster demo applications causes JBDS to throw up the following errors:
Errors occurred during the build.
Errors running builder 'JavaScript Validator' on project 'ticket-monster'.
11
as a modal pop-up dialog - normally popping up twice

In the problems tab:

Internal validation error
java.lang.ArrayIndexOutOfBoundsException: 11
at org.eclipse.wst.jsdt.internal.compiler.ast.CaseStatement.resolveCase(CaseStatement.java:82)
at org.eclipse.wst.jsdt.internal.compiler.ast.SwitchStatement.resolve(SwitchStatement.java:156)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:350)
at org.eclipse.wst.jsdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:137)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:304)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:375)
at org.eclipse.wst.jsdt.internal.compiler.ast.FunctionExpression.resolveType(FunctionExpression.java:58)
at org.eclipse.wst.jsdt.internal.compiler.ast.ObjectLiteralField.resolveType(ObjectLiteralField.java:70)
at org.eclipse.wst.jsdt.internal.compiler.ast.ObjectLiteral.resolveType(ObjectLiteral.java:80)
at org.eclipse.wst.jsdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:279)
at org.eclipse.wst.jsdt.internal.compiler.ast.Expression.resolve(Expression.java:477)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:350)
at org.eclipse.wst.jsdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:137)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:304)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:375)
at org.eclipse.wst.jsdt.internal.compiler.ast.FunctionExpression.resolveType(FunctionExpression.java:58)
at org.eclipse.wst.jsdt.internal.compiler.ast.ObjectLiteralField.resolveType(ObjectLiteralField.java:70)
at org.eclipse.wst.jsdt.internal.compiler.ast.ObjectLiteral.resolveType(ObjectLiteral.java:80)
at org.eclipse.wst.jsdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:279)
at org.eclipse.wst.jsdt.internal.compiler.ast.Expression.resolve(Expression.java:477)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:350)
at org.eclipse.wst.jsdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:137)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:304)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:375)
at org.eclipse.wst.jsdt.internal.compiler.ast.FunctionExpression.resolveType(FunctionExpression.java:58)
at org.eclipse.wst.jsdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:267)
at org.eclipse.wst.jsdt.internal.compiler.ast.Expression.resolve(Expression.java:477)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:350)
at org.eclipse.wst.jsdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:137)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:304)
at org.eclipse.wst.jsdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:375)
at org.eclipse.wst.jsdt.internal.compiler.ast.FunctionExpression.resolveType(FunctionExpression.java:58)
at org.eclipse.wst.jsdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:279)
at org.eclipse.wst.jsdt.internal.compiler.ast.Expression.resolve(Expression.java:477)
at org.eclipse.wst.jsdt.internal.compiler.ast.CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:394)
at org.eclipse.wst.jsdt.internal.compiler.Compiler.process(Compiler.java:604)
at org.eclipse.wst.jsdt.internal.compiler.Compiler.compile(Compiler.java:356)
at org.eclipse.wst.jsdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:288)
at org.eclipse.wst.jsdt.internal.core.builder.BatchImageBuilder.compile(BatchImageBuilder.java:86)
at org.eclipse.wst.jsdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:227)
at org.eclipse.wst.jsdt.internal.core.builder.BatchImageBuilder.build(BatchImageBuilder.java:58)
at org.eclipse.wst.jsdt.internal.core.builder.JavaBuilder.buildAll(JavaBuilder.java:291)
at org.eclipse.wst.jsdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:199)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:728)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:239)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:292)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:295)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:351)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:374)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:143)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:241)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)