[AMQ-5616] Declare variables as ConcurrentMap not ConcurrentHashMap to avoid issues after compiling on Java 8

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 5.11.1
• Fix Version/s: 5.12.0
• Component/s: Broker
• Assignee: Timothy A. Bish
• Reporter: Timothy A. Bish
• Created: 25/Feb/15 19:21
• Updated: 28/Apr/15 15:15
• Resolved: 28/Apr/15 15:15

Description

Java 8 redefines the method keySet() on ConcurrentHashMap to return a narrower type than the standard return type given in the Map interface. If the code is compiled in Java 8 and then run under Java 7 this causes linking issues. We don't depend on the narrowed type and can live with the standard for our usages of ConcurrentHashMap

We can avoid these issues by always declaring the instances of ConcurrentHashMap where we need method like putIfAbsent in terms of the interface ConcurrentMap