Conversion to Dalvik format failed: Unable to execute dex

最近莫名奇妙遇到“Conversion to Dalvik format failed: Unable to execute dex”错误，stackoverflow以后得到结果

把项目中classpath文件中<classpathentry kind="lib"   path ="自定义jar的地址" /> 修改成 <classpathentry kind="con" path="com.android.ide.eclipse.adt.ANDROID_FRAMEWORK"/>，删掉<classpathentry kind="con" path="com.android.ide.eclipse.adt.LIBRARIES"/>。然后就OK了