title: Dx bad class file magic (cafebabe) or version (0033.0000) with ADK14
body: <p>Since moving to ADK14, I have been unable to build new apks for release on my Windows 7 system.</p>
  
  <p>Building fails with "conversion to dalvik format failed with error 1", while the console is filled with lots of "Dx bad class file magic (cafebabe) or version (0033.0000)".</p>
  
  <p>The full exception text:</p>
  
  <pre><code>com.android.ide.eclipse.adt.internal.build.DexException: Conversion to Dalvik format failed with error 1
  at com.android.ide.eclipse.adt.internal.build.BuildHelper.executeDx(BuildHelper.java:740)
  at com.android.ide.eclipse.adt.internal.project.ExportHelper.exportReleaseApk(ExportHelper.java:204)
  at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard.doExport(ExportWizard.java:290)
  at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard.access$0(ExportWizard.java:229)
  at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard$1.run(ExportWizard.java:214)
  at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)
  </code></pre>
  
  <p>I am building an old project that uses lots of libraries, so presumably the problem is related to this fact. Already done all the "Fix Properties"/Clean etc that are suggested when moving to ADK14 (as I naturally had all those problems), but they haven't helped with this.</p>
  
  <p>All the libraries are on the same Android SDK and JDK/JRE version, so this wouldn't seem to be the issue.And in fact, the app is easily built in debug and installed on my old version 1.5 HTC Magic - it is only when I need to export a signed application package that this breaks down.</p>
  
  <p>[Edit]
  This is on a Windows 7x64 PC. I observe that packing the apk on my Linux laptop (Lucid Lynx) for the exact same code has absolutely no problems whatsoever.</p>
  
  <p>Any ideas? Getting very frustrated with this.</p>
  
  <p><strong>NOTE</strong></p>
  
  <p>Apparently, this error message can be triggered by a variety of different problems. My particular problem was not related to Java 6/7, as I never installed Java 7 in the first place, and compiler compliance was set to Java 6 (I checked at the time, as I had seen that solution suggested elsewhere).</p>