21. Producer consumer problem using wait() and notify

1. Producer consumer problem.

1. In computing, the producer–consumer problem (also known as the bounded-buffer problem) is a classic example of a multi-process synchronization problem.
2. The problem describes two processes, the producer and the consumer, which share a common, fixed-size buffer used as a queue.

• The producer’s job is to generate data, put it into the buffer, and start again.
• At the same time, the consumer is consuming the data (i.e. removing it from the buffer), one piece at a time.