Idea中JDK为1.8，还提示Diamond types are not supported at this language level

help------about查看ide的版本：

IntelliJ IDEA 2017.3.7 (Ultimate Edition)
Build #IU-173.4710.11, built on April 4, 2019
Licensed to Rover12421 / Rover12421
You have a perpetual fallback license for this version
Subscription is active until December 31, 2099
JRE: 1.8.0_152-release-1024-b18 amd64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Windows 7 6.1

新建的一个maven项目，一路点next创建的，结果 new KafkaProducer<>的时候报错：

Diamond types are not supported at this language level

 可以看到Diamond 是JDK1.7的特性，所以1.5肯定是不支持的。

右键项目，选择Open Module Setting

打开如下的弹窗，报错就是这里的Language level默认还是5.0