hg: jdk9/sandbox/jdk: 8156079: consider making empty instances singletons; ...

[chris.hegarty at oracle.com]

Changeset: 93e7c16fd885
Author:    smarks
Date:      2016-11-04 14:29 -0700
URL:       http://hg.openjdk.java.net/jdk9/sandbox/jdk/rev/93e7c16fd885

8156079: consider making empty instances singletons
8169222: minor immutable collections optimizations
Reviewed-by: forax, redestad, alanb

! src/java.base/share/classes/java/util/ImmutableCollections.java
! src/java.base/share/classes/java/util/List.java
! src/java.base/share/classes/java/util/Map.java
! src/java.base/share/classes/java/util/Set.java