Explain the use of "public static void main(String args[])"?

The line "public static void main(String args[])" is the signature of the main method, which is the entry point for a Java application. Here's what each part means:

1. public:
   This is an access modifier, which specifies that the method can be accessed from anywhere in the program. In this case, the main method needs to be public so that the JVM (Java Virtual Machine) can access it and execute the application.

2. static:
   This is a keyword that indicates that the method belongs to the class, rather than to any instance of the class. In other words, the main method can be called without creating an object of the class that contains it. This is necessary because the JVM needs to be able to execute the main method before any objects are created.

3. void:
   This is the return type of the main method, which means that it doesn't return any value. The main method is only responsible for starting the application and doesn't need to return any result.

4. main:
   This is the name of the method. The JVM looks for a method with this name in the class that is specified as the entry point for the application.

5. (String args[]):
   This is the parameter list for the main method. It specifies that the method takes an array of String objects as input, which is typically used to pass command-line arguments to the application. The name args is a convention, but you could choose any other valid identifier name instead.

Overall, the main method is the entry point for a Java program, and it must be defined with the exact signature "public static void main(String args[])". This is because the JVM expects to find a method with this signature in order to start the program. The use of public and static makes the method accessible to the JVM, while the use of void indicates that it does not return any value. The main name is a reserved name in Java and the (String args[]) parameter list allows for the passing of command-line arguments to the program.