title: Eclipse JDT Compiler (ECJ) throws NPE in Java 1.7
body: <p>I'm getting an NPE from the ECJ (version 4.2.1) compiler when running in JRE 1.7 the same project compiles properly on JRE 1.6.</p>
  
  <p>A <code>CompilationProgress</code> monitor shows that there are Total of 2493 tasks, but then I get the NPE.</p>
  
  <p>Any ideas?</p>
  
  <p>TIA</p>
  
  <pre><code>java.lang.NullPointerException
      at org.eclipse.jdt.internal.compiler.apt.util.EclipseFileManager.concatFiles(EclipseFileManager.java:202)
      at org.eclipse.jdt.internal.compiler.apt.util.EclipseFileManager.handleOption(EclipseFileManager.java:669)
      at org.eclipse.jdt.internal.compiler.apt.dispatch.BatchProcessingEnvImpl.(BatchProcessingEnvImpl.java:88)
      at org.eclipse.jdt.internal.compiler.apt.dispatch.BatchAnnotationProcessorManager.configure(BatchAnnotationProcessorManager.java:69)
      at org.eclipse.jdt.internal.compiler.batch.Main.initializeAnnotationProcessorManager(Main.java:3632)
      at org.eclipse.jdt.internal.compiler.batch.Main.performCompilation(Main.java:3737)
      at org.eclipse.jdt.internal.compiler.batch.Main.compile(Main.java:1679)
      at org.eclipse.jdt.internal.compiler.batch.Main.compile(Main.java:1372)
      at org.eclipse.jdt.core.compiler.batch.BatchCompiler.compile(BatchCompiler.java:80)
      at org.eclipse.jdt.core.compiler.batch.BatchCompiler.compile(BatchCompiler.java:52)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:601)
  ...
      at java.lang.Thread.run(Thread.java:722)
  </code></pre>