[HBASE-18878] Use Optional<T> return types when T can be null

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0-alpha-4, 2.0.0
• Component/s: Coprocessors
• Hadoop Flags: Incompatible change
• Assignee: Duo Zhang
• Reporter: Duo Zhang
• Created: 26/Sep/17 01:50
• Updated: 17/Jun/22 05:22
• Resolved: 05/Oct/17 00:37

Description

I've already done lots of Nullable to Optional change when purging the interfaces for CP. This is a big one so open a separated issue for it.