Null Pointer exception thrown if initString points to a directory, not a file.

java.lang.NullPointerException
	at com.cenqua.clover.instr.Instrumenter.startInstrumentation(Instrumenter.java:82)
	at com.cenqua.clover.instr.Instrumenter.startInstrumentation(Instrumenter.java:70)
	at org.apache.tools.ant.taskdefs.CloverCompilerAdapter.setJavac(CloverCompilerAdapter.java:336)
	at org.apache.tools.ant.taskdefs.Javac.compile(Javac.java:1062)
	at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:882)
	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
	at org.apache.tools.ant.Task.perform(Task.java:348)
	at org.apache.tools.ant.Target.execute(Target.java:357)
	at org.apache.tools.ant.Target.performTasks(Target.java:385)
	at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)