What a Lock Gives You, and What It Does Not

Five things this topic established, and where each one was.

What the topic established, and which card it was on
The thing	Where
A `synchronized` instance method locks `this`; the static form locks the class	Why a static synchronized Method Does Not Lock the Instance
Leaving a lock publishes everything written inside it, to anyone entering the same lock	The Second Guarantee
Locks are reentrant, held by the thread rather than the block	Re-entering a Lock You Are Already Holding
`ReentrantLock` adds timeouts and interruptibility, and needs a `finally`	synchronized Against ReentrantLock
Every method being atomic says nothing about a sequence of two	Why Synchronizing Every Method Did Not Make the Class Thread-Safe

A lock protects a region, and the region has to be as large as the operation. Deciding where the operation really starts and ends is the whole of the work, and the keyword does none of it for you.

Java
Concurrency