GATK Error: UnsupportedClassVersionError - Java Runtime Version Mismatch

This error occurs because the version of Java Runtime used to execute the GATK command is older than the version used to compile the GATK jar file. In this case, the GATK jar file has been compiled with Java Runtime version 61.0, while the Java Runtime used to execute the command only recognizes class file versions up to 52.0.

To resolve this error, you should update the Java Runtime on your system to a version that is compatible with the GATK jar file. You can check the version of Java Runtime installed on your system by running the command 'java -version' on the command line.

Once you have updated your Java Runtime, you can try running the GATK command again.