Solution:
The language level is determined to be above 1.6, OK.
If the following exception occurs after solving the Override problem:
Error:java: Compilation failed: internal java compiler error
Then set the following page settings in settings:
I personally tried it, and the Target bytecode version is determined to be above 1.6, and there is no problem.
However, there is still a problem after the project is refreshed, and it is found that the version has changed back to 1.5. How did this happen:
in the project's pom.xml
<build>
<plugins>
<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>
</plugins>
</build>