add synchronization to ensure proper intializaiton and closing of PCM…

[antonmos]

…etrics singleton. fixes #617

Fixes NPE during shutdown described in #617

Checklist

• Documentation (if applicable)
• Changelog

[what-the-diff]

PR Summary

• Version Update in Change-log

  • The change-log documentation was updated to reflect the introduction of a new software version 0.5.2.7. Features of this version include improved synchronization methods to enhance functioning of a component called PCMetrics.

• Addition and Modification in PCMertics Java File

  • A new component called Timer was incorporated into the PCMetrics file via an import statement.
  • Import statements related to different functionalities from java.util were streamlined under java.util.* improving the code simplicity.
  • A previously private field, registeredMeters, was updated from a standard List to a synchronized List. This change enhances the field's security and safeguards it against potential simultaneous alterations.

• Adds Synchronization to Methods

  • Certain methods - 'initialize', 'close' and 'removeMeter' were revamped with synchronization techniques. This would improve these methods' efficiency by preventing multiple threads from executing the code at the same time.

• Code Formatting Improved

  • The code formatting was enhanced with additional indents and new lines to improve readability and maintainability.

[cla-assistant]

All committers have signed the CLA.

[jhollandus]

LGTM

[jhollandus]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.1 out of 2 committers have signed the CLA.✅ eddyv❌ antonmosYou have signed the CLA already but the status is still pending? Let us recheck it.

Hi @antonmos, we need you to sign the CLA to contribute this PR. Thanks.

[antonmos]

signed it. thank you!

[antonmos]

thanks for merging! any idea when you will release a new version?

[krvajal]

I got it working with https://jitpack.io/