Windows runner error about Java Runtime class file versions

Problem

You attempt to start a Windows self-hosted runner and you get an error like the following:

Environment

Windows self-hosted runners in Bitbucket Pipelines.

Cause

The error message states that the version of Java on the Windows machine where you attempt to start the runner only recognizes class file versions up to 52.0.

The table in the following page lists Java class file versions for each JDK release

• https://javaalmanac.io/bytecode/versions/

The class file version 52.0 mentioned in the error message corresponds to Java 8, so this is the version of Java used by your Windows machine.

A prerequisite for the Windows runner is that OpenJDK 11 (11.0.15 or newer) is installed on the host machine where you want to run the runner:

• https://support.atlassian.com/bitbucket-cloud/docs/set-up-runners-for-windows/

Solution

Uninstall Java from the Windows machine and install OpenJDK 11.0.15 or newer:

• https://openjdk.org/install/