We know Java supports three types of classes – Concrete, abstract and interfaces. After summarizing the difference between abstract classes and interfaces, let us tabulate the difference between classes and interfaces.
| Supports only multilevel and hierarchical inheritances but not multiple inheritance | Supports all types of inheritance – multilevel, hierarchical and multiple |
| "extends" keyword should be used to inherit | "implements" keyword should be used to inherit |
| Should contain only concrete methods (methods with body) | Should contain only abstract methods (methods without body) |
| The methods can be of any access specifier (all the four types) | The access specifier must be public only |
| Methods can be final and static | Methods should not be final and static |
| Variables can be private | Variables should be public only |
| Can have constructors | Cannot have constructors |
| Can have main() method | Cannot have main() method as main() is a concrete method |
Know also the differences between abstract class vs interface.
very nice articel sir hats of you
Can we create our own marker interface ? If yes how and if no how ?
Please explain.