idea jdk明明是1.8了,还是 出现Diamond types are not supported at this language level
三个地方
- project structure中的project ,SDK选择1.8,Project language level选择8
- project structure中的module,选择Language level为8
- setting中的java compiler
maven配置
<!--控制项目的language level和compile 版本-->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>