What is the relation between the main() method and main thread in Java?

java multithreading main
Java_begins picture Java_begins · Jul 16, 2013 · Viewed 14.3k times · Source

My tutor told me that the main thread is the parent thread of every thread, but he is not able to explain why.

When I write a simple program:

Class A{}

Then it at the time of execution it throws an exception:

java.lang.NoSuchMethodError: main Exception in thread "main"

Is there any relation between the main() method and the main thread?

Answer

Thilo picture Thilo · Jul 16, 2013

Is there any relation between main() method and Main Thread ?

When the JVM starts, it creates a thread called "Main". Your program will run on this thread, unless you create additional threads yourself.

The first thing the "Main" thread does is to look for your static void main(String[] argv) method and invoke it. That is the entry-point to your program.

If you want things to happen "at the same time", you can create multiple threads, and give each something to execute. They will then continue to do these things concurrently. The JVM also creates some internal threads for background work such as garbage collection.

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