Android之failed for task ':app:dexDebug'致gradle编译OOM问题解决（android-support-multidex）

                  当我们的业务越来越多，项目里面的方法和第三方的jar包也会越来越多，然后昨晚就遇到了下面这个问题

        UNEXPECTED TOP-LEVEL EXCEPTION:
	at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:596)
	at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:554)
        com.android.dex.DexException: Multiple dex files define Lcom/tencent/a/a/a/a/a;
	at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:535)
	at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:171)
	at com.android.dx.merge.DexMerger.merge(DexMerger.java:189)
	at com.android.dx.command.dexer.Main.mergeLibraryDexBuffers(Main.java:502)
	at com.android.dx.command.dexer.Main.runMonoDex(Main.java:334)
	at com.android.dx.command.dexer.Main.run(Main.java:277)
	at com.android.dx.command.dexer.Main.main(Main.java:245)
	at com.android.dx.command.Main.main(Main.java:106)
Error:Execution failed for task ':app:dexDebug'.
> com.android.ide.co