public - The main method is called by the JVM to run the method which is outside the scope of the project therefore the access specifier has to be public to permit a call from anywhere outside the application.
static - When the JVM makes a call to the main method there is no object that exists for the class being called therefore it has to have static method to allow invocation from class.
void - Java is a platform independent language, therefore if it returns some value, then the value may have a different meaning between different platforms so unlike C it can not assume a behavior of returning value to the operating system.