Why java is multi threated?

Answer 1

Why shouldn't it? Multithreading is an advantage, because it lets you make full use of a computer with multiple processors. Mind you, you don't HAVE TO use it - you can perfectly well write programs without multithreading. But in actual practice, many situations arise where you want the computer to do several things at once. Even with a single processor, multithreading offers a convenient way to share the computer time between different tasks.