Invoke isAlive() or join()

Question

When I invoke isAlive(), I saw the code form like: m.thrd.isAlive(). m implements runnable interface. thrd is the object of Thread.

I understand isAlive() is the method of Thread class, we use Thrd.isAlive() to invoke. And we need to let it know m is the thread should be die first. But how to understand object.object.method this format?

Thanks in advance

Answer 1

This has nothing not do with multi-threading; this is purely about Java syntax rules and the semantics of the "." in java statements. What you got here is:

a class that has a field m

m than has a field thrd

thrd has a method isAlive().

In other words. m.thrd.isAlive() accesses a field m, to access a field thrd, to access a method isAlive().

Btw: terrible naming - one shouldn't use one letter names for variables, and there is absolutely no point in using an abbreviation like "thrd" either. That just confuses the reader.