Why is the word "join" is used for the Thread.join() method?

Question

I started to do research to find out why the word "join" is used for the Thread.join() method. In fact, it waits for the thread to end on which it is called and pauses the main thread to wait for it so, there is nothing to join. So, its name should be something like:

1. Thread.pauseCaller();
2. Thread.freezeCaller();
3. Thread.focusThread();
4. Thread.runBefore();

I found one simple sentence after too much research which says that:

Thread.join(); name comes from the concept of the calling thread waiting until the specified thread joins it.

I am totally unable to get this above sentence into my mind and failed to understand the background context of using the word join for this method. What does the word "join" represent in this context? There is nothing to join anything else; instead, it just pauses the calling thread to wait for the thread followed by the join(). So, can anyone tell the context of using the join word for this method?

Answer 1

The word "join" comes from the Fork–Join model, where "fork" means to split the thread into multiple threads for parallel processing, and "join" means to wait for the parallel threads to complete their part, before continuing in a single thread.