Sanne Grinovero ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HHH-16440 ( https://hibernate.atlassian.net/browse/HHH-16440?atlOrigin=eyJpIjoiNTg1Yz... ) Re: Classleak in the BytecodeProviderImpl ( https://hibernate.atlassian.net/browse/HHH-16440?atlOrigin=eyJpIjoiNTg1Yz... ) Could you elaborate on why each of your integration tests needs to create a new SessionFactory? Your tests could run much faster if that wasn’t the case, and - like you’ve seen - there’s many problems for us in caching things within a static global scope w/o polluting the classloader. Most of our users, as far as I know, either run in modular environments which would dump the classloader after a deployment is terminated, or work on the opposite spectrum: a simple single classloader, but have the application booted only once. Taking a step back, perhaps Hibernate shouldn’t store any state at all in such a static scope; unfortunately generating new class definitions within the current classloader will have this side-effect. It might not be obvious and we might log some warnings about it, but this won’t solve the problem you’re reporting. ( https://hibernate.atlassian.net/browse/HHH-16440#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16440#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100228- sha1:e911e2c )