[WW-5009] EmptyStackException in JSON plugin due to concurrency

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.5.20
• Fix Version/s: 2.5.22, 6.0.0
• Component/s: Plugin - JSON
• Labels: json json-rpc

Environment

JDK 1.8_0_191

Tomcat 9.0.12

• Assignee: Aleksandr Mashchenko
• Reporter: Eduardo Quintanilla
• Created: 29/Jan/19 14:10
• Updated: 02/Nov/21 06:07
• Resolved: 05/Feb/19 11:44

Description

EmptyStackException in JSON plugin due to concurrency

Note: The issue was found in an app that was upgraded from version 2.3.34 

Logs: logs.txt

I created a sample application that should help reproducing the error.

struts-json-example-master.zip

The error happened opening the app (localhost/struts-json-example) in 4 different browsers / sessions.

As a workaround I have overridden the JSONInterceptor so a new instance of JSONUtil is used with every request and the issue is not happening anymore. I suppose there is a performance cost with that change but for now it works.

 

Issue Links

• relates to: WW-4034 Allow to use custom JSONwriter
• links to: GitHub Pull Request #326
• links to: GitHub Pull Request #328
• links to: GitHub Pull Request #329