【Android】org.gradle.api.internal.tasks.compile.CompilationFailedException: Compilation failed

项目更新代码后无法运行，会报如下错误：

org.gradle.api.internal.tasks.compile.CompilationFailedException: Compilation failed; see the compiler error output for details.
at com.android.build.gradle.tasks.factory.AndroidJavaCompile.compile(AndroidJavaCompile.java:92)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
at java.lang.Thread.run(Thread.java:745)

clean，rebuild 都试过，找了半天没找到问题在哪。
后来才发现，注意一下报错的第一行有一句：
see the compiler error output for details. 查看编译器的错误输出详情

原来 build - Java Compiler 里已经告诉我们具体出错的位置了