Unzip the attached sources into your contrib/checkout and try to do something
with them;  just about any operation (right click in the editor, whatever)
results in the following:

com.sun.tools.javac.util.FatalError: Fatal Error: Unable to find package
java.lang in classpath or bootclasspath
	at com.sun.tools.javac.comp.MemberEnter.importAll(MemberEnter.java:123)
	at com.sun.tools.javac.comp.MemberEnter.visitTopLevel(MemberEnter.java:509)
	at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:446)
	at com.sun.tools.javac.comp.MemberEnter.memberEnter(MemberEnter.java:387)
	at com.sun.tools.javac.comp.MemberEnter.complete(MemberEnter.java:849)
	at com.sun.tools.javac.code.Symbol.complete(Symbol.java:384)
	at com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:760)
	at com.sun.tools.javac.comp.Enter.complete(Enter.java:482)
	at
org.netbeans.api.java.source.JavaSource$ErrorHandlingJavadocEnter.main(JavaSource.java:722)
	at com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:819)
	at com.sun.tools.javac.api.JavacTaskImpl.enter(JavacTaskImpl.java:345)
	at com.sun.tools.javac.api.JavacTaskImpl.enter(JavacTaskImpl.java:291)
	at org.netbeans.api.java.source.JavaSource.moveToPhase(JavaSource.java:781)
	at org.netbeans.api.java.source.JavaSource$CompilationJob.run(JavaSource.java:1026)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
[catch] at java.lang.Thread.run(Thread.java:619)