[JENA-1953] EnvJavaScript is supposed to be a singleton. However EnvJavaScript.get may return multiple instances

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: Jena 3.17.0
• Component/s: ARQ
• Assignee: Andy Seaborne
• Reporter: Pavel Mikhailovskii
• Created: 27/Aug/20 10:54
• Updated: 01/Dec/20 14:32
• Resolved: 28/Aug/20 16:44

Description

EnvJavaScript is supposed to be a lazily-initialized singleton but the implementation is broken. It uses a non-volatile static field which is not lock-guarded when read. As a result , EnvJavaScript.get may instantiate multiple instances.