There is a list of Milestone that are currently being worked on for this feature.   The due date in the dev plan is the date to provide this list of milestone.    Once the list is available the final due date to deliver all these milestone will be updated.

First draft high-level steps --

I) Language Support (modified javac)
I.a)   Prototype top-level statements, expressions, variable declarations, and method declarations
I.b)   SPI for REPL tool access

II) Interactive command-line REPL tool
II.a)   Non-repetitive non-edited REPL partitioning
II.b)   Non-repetitive non-edited REPL compilation
II c)   Expression evaluation/printing
II.d)   Editing (by repetition?) support

First draft high-level milestones --

A) Non-interactive (batch) compilation of the proposed language -- July 2014
B) Interactive REPL tool partitions input by intact top-level language element: package and import declaration, class, variable declaration, method declaration, statement, expression, incomplete, or error -- Sept 2014
C) Tool compiles the elements -- Nov 2014
D) Tool dynamically executes -- Dec 2014
E) Tool completes missing semi-colons -- Jan 2015
F) Tool completes missing type declarations in variable declarations -- Apr 2015
G) Editing of input by repetition or other mechanism -- Jul 2015