Multi-threading - basic principle of thread pool (create commit and close configuration)

Thread Pool:

The benefits of thread pools (why use ThreadPool):

Implementation principle:

ThreadPoolExecutor:

Execution diagram:

There are 4 situations in which the execute method is executed:

Execute underlying code implementation:

Schematic diagram of thread execution tasks:

Thread pool creation:

Submit a task to the thread pool:

Two submission methods: execute / submit 

Close the thread pool:   

Reasonable configuration thread pool:

Monitor the thread pool: