[UIMA-6398] Classloader paradoxon and memory leak in UIMA loggers

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.3.0SDK
• Component/s: Core Java Framework
• Assignee: Richard Eckart de Castilho
• Reporter: Richard Eckart de Castilho
• Created: 09/Dec/21 14:54
• Updated: 02/May/22 13:00
• Resolved: 10/Dec/21 14:57

Description

The UIMAFramework_impl singleton contains a map mLoggers which caches all the UIMA logger wrapper classes. The UIMA logger wrapper classes all inherit from org.apache.uima.util.impl.Logger_common_impl which in turn holds a reference to a resource manager.

This resource manager is set in

• FlowControllerContainer.initialize
• PrimitiveAnalysisEngine.initialize
• Resource_ImplBase.initialize

to the resource manager from the UIMAContext available in the respective situation. However, the logger wrapper instances cached in UIMAFramework_impl are shared globally so that it is very likely in multi-threaded/multi-classloader that resource managers from different contexts override each other and that when a message in a given context is logged, the wrong resource manager is used.

Furthermore, any resources registered in a resource manager that is attached to a logger won't be garbage collected - at least not until a new resource manager is set.

Issue Links

• links to: GitHub Pull Request #159