Using Incompatible version of JDK can cause the Server side GemFire functions to fail

Products

• VMware Tanzu Gemfire

Issue/Introduction

The issue appears when function classes are compiled with one version of the JDK and then the jars are deployed on VMWare Tanzu GemFire servers running on an incompatible version of the JDK (For instance, compiling with JDK 11 and deploying to VMWare Tanzu GemFire 1.12, which runs on JDK 8). Those functions when executed will fail with an exception similar to the below:

2020-11-18T09:51:54.963-05:00 [APP/PROC/WEB/0] [OUT] Caused by: java.lang.LinkageError: loader (instance of org/apache/geode/internal/DeployJarChildFirstClassLoader): attempted duplicate class definition for name: "<function>"

Environment

Product Version: 1.12

Resolution

Compile the server side jars with the compatible versions of the JDK (JDK 8 in this case).