Gradle has a bunch of command-line options that will print out the tree and any overrides, you can also query a particular jar to see its dependency list. It may help you diagnose the problem. Look for common transitives with an overridden version. Less likely but possible problems: JAVA_HOME or CLASSPATH being overridden, dynamically loaded jars, corrupted POMs, or java module problems if you are using 9 or above.