tree 44f2ee79b148dd9dab989f71829f90f1b117bd60
parent 1e19aefa6f9e2368f34745bc0eb38dc2618e4f06
author Hugo Benichi <hugobenichi@google.com> 1476344922 +0900
committer Lorenzo Colitti <lorenzo@google.com> 1485424309 +0900

ConnectivityThread: use lazy holder idiom

This patch changes the way that the ConnectivityThread is lazily
instantiated by using the "lazy initialization holder class idiom".

The first code point that tries to obtain a reference to the unique
ConnectivityThread instance will trigger the creation of the Singleton
class, which will guarantee a thread-safe initialization of the static
INSTANCE field inside Singleton according to the language specs.

This is the Item #71 of Effective Java.

The unique static instance of ConnectivityThread is not stored directly
inside ConnectivityThread class but is stored in a static nested class.
This is to avoid triggering the creation of that unique instance when
Zygote does class preloading at phone startup. Otherwise this would lead
to Zygote creating a new OS thread during preloading, which is a fatal
error.

Test: frameworks-wifi tests pass
Bug: 26749700
Bug: 28537383
Bug: 32130437

(cherry picked from commit c4fe5d373caa9f53686e4d58e61394dd40558957)

Change-Id: If13b363889a8e9396273a90c3d9f9421a48aecbc