Multi threading – performance

Multi threading – synchronization, sharing of resources multi threads access, multiple threads running in a system. One of the thread can modify shared variable while another thread is in the process of updating same shared variable. inheriting from Thread class, runnable interface. Handle multiple clients at the same time. The methods that are used for inter thread communication are wait(), notify() and notifyall(). When a thread terminates its processing, it enters the dead state. A lock can be acquired on a class.
The OS (operating systems) systems task scheduled allocates execution time to multiple tasks.

Synchronized can be defined at Method level or for a block as the statements within {}

Performance concerns of I/O- Threads block on i/o – it enters the waiting state, meanwhile the other threads may execute while the i/o Operation is performed. Changing the multi-threading level improves performances and reliability.