Lets re-look at the Java Sample Program - Simple Hello World Program In Java
which was discussed long time back. Now that we understand classes, methods and there return types, static methods, arrays and access specifiers, lets see how the simple java program which was very confusing then, will be very clear now.
public static void main(String args)
class: In Java, every line of code/statement should be included as part of a class, that is the reason, we have defined a
class with the name of the program
main: When we run the program using
java PrintHelloWorld it will look for the method
main in the class
PrintHelloWorld. The method
main is the starting point of execution of the program.
static: If we want to call a method, we should have an object, since we can not create an object without going into main method, it will become a problem. If we make the
main method as
static then we can call it with out creating any object.
public: Since the
main method should be accessible from outside of the program and probably from different packages, you need to make it
public. If you make it
default, then the method can not be accessed from a different package.
void: Even if return any parameter from the
main method, the program does not know what to do with it. If you want to return a process exit code, we should use the method
System.exit and the not return the value from
String: One way to pass parameters to java program, is to use the command line arguments. When we run the program with command line arguments, the arguments are converted into a
String array and passed as a parameter to the