java 5 level lambd can not use

1. settings

![(https://img-blog.csdnimg.cn/20190801205217132.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hheWFxaTA1MDQ=,size_16,color_FFFFFF,t_70)


2 another method

in maven: you can use

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <!--修改Language level-->
    <maven.compiler.source>1.8</maven.compiler.source>
    <!--修改Java Compiler-->
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>