Error:Execution failed for task ':app:transformClassesWithDexForDebug'

问题描述：

Error:Error converting bytecode to dex:
Cause: java.lang.RuntimeException: Unexpected exception in dex writer thread

Error:Execution failed for task ':app:transformClassesWithDexForDebug'.
> com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: Error while executing java process with main class com.android.dx.command.Main with arguments {--dex --num-threads=4 --multi-dex --main-dex-list D:\workspace\android\mjhome\app\build\intermediates\multi-dex\debug\maindexlist.txt --output D:\workspace\android\mjhome\app\build\intermediates\transforms\dex\debug\folders\1000\1f\main D:\workspace\android\mjhome\app\build\intermediates\transforms\jarMerging\debug\jars\1\1f\combined.jar}

问题原因：

To run dex in process, the Gradle daemon needs a larger heap.
It currently has 512 MB.
For faster builds, increase the maximum heap size for the Gradle daemon to at least 1536 MB.
To do this set org.gradle.jvmargs=-Xmx1536M in the project gradle.properties.

解决方法：

更改 gradle.properties 配置文件，把 org.gradle.jvmargs=-Xmx512m 改成 org.gradle.jvmargs=-Xmx1536m 就可以了。