Java Backend Developer Interview Questions (Pt. 31–40)

31. What are the basic states of a thread?

NEW: The thread instance is newly created.

RUNNABLE: RUNNBALE has both READY and RUNNABLE states. When start() is invoked, the thread goes into READY state to wait for the system to allocate a timeslice.

RUNNING: The CPU allocates the time slice to the thread so the thread can execute.

BLOCKED: The thread is blocked when it tries to access some resource but the lock of that resource is acquired by other threads.

WAITING: The thread goes into waiting for the state until other threads notify or interrupt so it can re-enter Runnable state.

TIMED_WAITING: The thread goes into TIME_WAITING when the program puts a maximum timeout on the thread.

TERMINATED: The thread finishes and exits.

32. Why does it execute run() when we call start() instead of calling run() directly?

start() allows the thread to enter into a Runnable state. When the thread gets allocated time…