Reducing Classloader's parallelLockMap memory consumption proposal

[Dmytro Ukhlov]

Hello!

I created PR is scope of jenkins-core project:
https://github.com/jenkinsci/jenkins/pull/10659
Jira ticket: https://issues.jenkins.io/browse/JENKINS-75675

In this PR i propped to override
protected Object getClassLoadingLock(String className)
method and use weak references for lock objects

Jenkins is a plugable platform, each plugin has its own class loader
and its parallelLockMap may consume 10mb of RAM. As a result it might
have 2gb overhead if ~200 plugins installed.

Jenkins maintainers ask me to consider making this improvement in base