Java. Lang. unsupportedclassversionerror: bad version number in. Class File

The class version is not supported. It indicates that the JDK or server version is incorrect during compilation or running.

1. To run a compiled project file, the version of the runtime environment in which it is located should be no less than the version at the time of compilation. Therefore, JDK should be set in two places in the eclipse environment to comply with this rule.

• Right-click the project file and click Properties for configuration. in Java build path, select JDK version.
• Java compiler is set by the compiler. The level here should be less than or equal to the JDK version in build path.

2. Find the place where servers is set in eclipse or myeclipse. Generally, Tomcat is used. Select a version of Tomcat. JDK related to this version is set to the current JDK version.

All three items must be modified to avoid errors.