How threads work

• A thread is a single sequential flow of control within a program. A thread often completes a specific task.
• By default, a Java application uses a single thread, called the main thread.
• However, some programs can benefit by using two or more threads to allow different parts of the program to execute simultaneously.
• On a computer that has just one central processing unit, or CPU, the threads don't actually execute simultaneously. Instead, a part of the Java virtual machine called the thread scheduler alternately lets portions of each thread execute.
• This gives the appearance that all of the tasks are running at the same time. And it can make an application work more efficiently.