title: Error when using a jar in my project
body: <p>I use Java 1.8 to create my jar.</p>
  
  <p>I can use it in a Java project, but in an Android project, I have the following error:</p>
  
  <pre><code>Error:Error converting bytecode to dex:
  Cause: Dex cannot parse version 52 byte code.
  This is caused by library dependencies that have been compiled using Java 8 or above.
  If you are using the 'java' gradle plugin in a library submodule add 
  targetCompatibility = '1.7'
  sourceCompatibility = '1.7'
  to that submodule's build.gradle file.
  Error:1 error; aborting
  Error:Execution failed for task ':app:transformClassesWithDexForDebug'.
  &gt; com.android.build.api.transform.TransformException: java.lang.RuntimeException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'E:\Android-tool\JAVA\jdk1.8.0_77\bin\java.exe'' finished with non-zero exit value 1
  Information:BUILD FAILED
  Information:Total time: 6.468 secs
  Information:3 errors
  Information:0 warnings
  Information:See complete output in console
  </code></pre>