[java] IntelliJ: Error:java: error: release version 5 not supported

The solution to the problem is already defined in some of the answers. But there is still a need to express a detail. The problem is totally related to maven, and the solution is also in the pom.xml configuration. IntelliJ only reads maven configuration, and if the configuration has wrong information, IntelliJ also tries to use that.

To solve the problem, as expressed in the most of the answers, just add the below properties to the pom.xml of the project.

<properties> 
      <maven.compiler.source>1.8</maven.compiler.source> 
      <maven.compiler.target>1.8</maven.compiler.target> 
</properties>

After that, on the IntelliJ side, reimport maven configuration. To reimport the maven configuration, right click on pom.xml file of the project and select Reimport. Compiler version related information in IntelliJ preferences will be automatically updated according to the values in the pom.xml.