Java Concurrency

Golden Rules

1. Make it right
2. Make it fast

Approach for this

1. Try to move the locks as lower as possible
2. Try to be thread-safe (use only immutable or no states at all)

KeyWords: Race Condition: Multiple threads are trying to acquire the resources.

Data Race: Typically check and update kind of cases where, the date that got modified is up for access immidiatly for update and read.

Main components

• Executor
• ExecutorService
• ScheduledExecutorService
• Future
• CountDownLatch
• CyclicBarrier
• Semaphore
• ThreadFactory
• BlockingQueue
• DelayQueue
• Locks
• Phaser

Life Cycle of Thread

Java.util.concurrent

The Interfaces in this package are classified on prilimnary levels as collection related and concurrency tools & mechanisms:

The classes in this package are classified on prilimnary levels collection and concurrency tools & mechanisms;

Lets take a closer look at those in Concurrency Handling column and try to re-classify them into differnt groups.

Collection

Future Flow

Executor Flow

CountDownLatch

Exchanger

Phaser

Remaining tools

• CyclicBarrier
• Executors
• Phaser
• Semaphore
• ThreadLocalRandom
• ForkJoinWorkerThread
• CompletionService