Planned lessonMID-004-L04

Explicit locks

On This Lesson 4 topics

This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.

In this lesson

know when ReentrantLock beats synchronized.

ReentrantLock offers tryLock (with timeout), interruptible locking, and fairness options.
Always unlock in finally.
ReadWriteLock/StampedLock help read-heavy data, but measure before adopting.
Condition replaces wait/notify with several wait sets.
Default to synchronized for simplicity; use explicit locks for the extra features.

Draft outline details

java

if (lock.tryLock(100, TimeUnit.MILLISECONDS)) {
    try { reserve(qty); } finally { lock.unlock(); }
}

Where must unlock() go?

Show answer

In a finally block.

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