Java config FactoryBean proxy causes class loader leak [SPR-9274]

[spring-projects-issues]

Harald Wellmann opened SPR-9274 and commented

Redeploying my web application in Tomcat a couple of times in a row, I had a PermGen space OutOfMemoryError. A heap dump revealed the cause to be a net.sf.cglib.proxy.Callback stored in thread-local memory, so that the associated class loader could not get garbage collected.

The callback holds a reference to ConfigurationClassEnhancer.GetObjectMethodInterceptor, which brought me closer to the root cause of the problem.

After changing my Spring Configuration from

    @Bean
    public PlatformTransactionManager transactionManager() {
        return new JpaTransactionManager(myEntityManagerFactory().getObject());
    }

    @Bean
    public AbstractEntityManagerFactoryBean myEntityManagerFactory() {
        LocalContainerEntityManagerFactoryBean bean = new LocalContainerEntityManagerFactoryBean();
        bean.setDataSource(myDataSource);
        bean.setPersistenceProvider(new HibernatePersistence());
        bean.setPersistenceUnitName("myPU");
        return bean;
    }

to

    @Bean
    public PlatformTransactionManager transactionManager() {
        return new JpaTransactionManager(myEntityManagerFactory());
    }

    @Bean
    public EntityManagerFactory tcmEntityManagerFactory() {
        LocalContainerEntityManagerFactoryBean bean = new LocalContainerEntityManagerFactoryBean();
        bean.setDataSource(myDataSource);
        bean.setPersistenceProvider(new HibernatePersistence());
        bean.setPersistenceUnitName("myPU");
        bean.afterPropertiesSet();
        return bean.getObject();
    }

I can redeploy my application without memory leaks.

I suspect the problem would disappear if ConfigurationClassEnhancer.enhanceFactoryBean() called Enhancer.registerStaticCallbacks() instead of Enhancer.registerCallbacks() (see #10601).

---

Affects: 3.1 GA, 3.2.8

Issue Links:

• Concurrent creation of the same Configuration class in different contexts is not thread-safe [SPR-10307] #14941 Concurrent creation of the same Configuration class in different contexts is not thread-safe
• Singleton-scoped @Bean methods behave like prototypes in a Spring DM environment [SPR-5932] #10601 Singleton-scoped @Bean methods behave like prototypes in a Spring DM environment

Backported to: 3.2.9

5 votes, 5 watchers

[spring-projects-issues]

Peter Ertl commented

I can confirm this memory issue and it's pretty serious imho. It actually wasted so much memory on our integration system (> 1GB) that in the end the tests died with OOME, taking forever since GC was using up most of time (> 1h30m instead of 16min). I would upgrade the severity to at least 'serious' since having this bug means that people upgrading to javaconfig will have tests that do not run in a real-life application.

I created a local copy of class org.springframework.context.annotation.ConfigurationClassEnhancer and replaced
Enhancer.registerCallbacks() with Enhancer.registerStaticCallbacks() as Harald suggested. That fixed the issue here.

[spring-projects-issues]

Peter Ertl commented

I would also suggest to add a call to Enhancer.registerCallback(obj.getClass(), null) in DisposableBeanMethodInterceptor to clean up thread local callbacks like that:

  private static class DisposableBeanMethodInterceptor implements MethodInterceptor {

    @Override
    public Object intercept(final Object obj, final Method method, final Object[] args, final MethodProxy proxy) throws Throwable {
      Enhancer.registerStaticCallbacks(obj.getClass(), null);
      >>>>  Enhancer.registerCallbacks(obj.getClass(), null);

[spring-projects-issues]

Juergen Hoeller commented

The underlying problem has been addressed in the 4.0 line through a wider-scale revision of configuration class processing (#14941).

That said, since that registerCallbacks call in enhanceFactoryBean is still there in the 3.2.x line, I'll locally fix it there as well - for the 3.2.9 release.

Sorry that it took so long... This issue unfortunately wasn't ever noticed.

Juergen