The difference between regular (non-static) and static methods

Java is object-oriented, but once in a while you have a special case, typically a utility method (like the Math methods), where there is no need to have an instance of the class. The keyword static lets a method run without any instance of the class. A static method means “behavior not dependent on an instance variable, so no instance/object is required. Just the class.”

Call a static method using a class name

Call a non-static method using a reference variable name