The code uses Logger.getLevel(), but doesn't take into account that the
value could be null. Exception trace:

java.lang.NullPointerException
     at
jdk.nashorn.internal.runtime.DebugLogger.levelAbove(DebugLogger.java:129)
     at jdk.nashorn.internal.codegen.Compiler.compile(Compiler.java:352)
     at jdk.nashorn.internal.runtime.Context.compile(Context.java:887)
     at jdk.nashorn.internal.runtime.Context.compileScript(Context.java:844)
     at jdk.nashorn.internal.runtime.Context.compileScript(Context.java:387)



Reported by Tal Liron @ nashorn-dev.