问题描述 

Idea启动项目报错：FAILURE: Build failed with an exception.

* Where:
Initialization script 'C:\Users\fudingwei\AppData\Local\Temp\Test3_main__.gradle' line: 81

* What went wrong:
Execution failed for task ':study:Test3.main()'.
> The value for task ':study:Test3.main()' property 'mainClass' is final and cannot be changed any further.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 8s

问题分析

Gradle 构建报错，应该是gradle的配置错了

解决办法

问题完美解决！！！