War deployment in standalone Tomcat causes webclassloader memory leak

[topu]

During startup Spring Boot invokes SLF4JBridgeHandler.install() to add a logging handler to container's LogManager, but during application shutdown (undeploy) adequate SLF4JBridgeHandler.uninstall() or SLF4JBridgeHandler.removeHandlersForRootLogger() is not called. I think it should be.

The bug manifests itself in taking metaspace memory space and following message is displayed after invoking Tomcat's find leaks method:
Message:

The following web applications were stopped (reloaded, undeployed), but their
classes from previous runs are still loaded in memory, thus causing a memory
leak (use a profiler to confirm):
/spring-boot-logging-issue

Below is my workaround that solves the issue. It removes the logging handler during ContextClosedEvent.

@Bean
public ApplicationListener<ContextClosedEvent> uninstallSLF4JBridgeHandlerWorkaround() {
    return new ApplicationListener<ContextClosedEvent>() {
        @Override
        public void onApplicationEvent(ContextClosedEvent event) {
            try {
                SLF4JBridgeHandler.removeHandlersForRootLogger();
            } catch (NoSuchMethodError ex) {
                SLF4JBridgeHandler.uninstall();
            }
        }
    };
}

Tested with Tomcat 8.0.15 and OpenJDK 1.8.0_25 on Linux 3.17.6

[wilkinsona]

LogbackLoggingSystem has the same problem in 1.1.x