Why interface is used in Java instead of multiple inheritance?

An interface contains variables and methods like a class but the methods in an interface are abstract by default unlike a class. Multiple inheritance by interface occurs if a class implements multiple interfaces or also if an interface itself extends multiple interfaces.

What is used in Java instead of multiple inheritance?

Java supports multiple inheritance through interfaces only. A class can implement any number of interfaces but can extend only one class. Multiple inheritance is not supported because it leads to deadly diamond problem.

Can we put a static method in interface?

Similar to Default Method in Interface, the static method in an interface can be defined in the interface, but cannot be overridden in Implementation Classes. To use a static method, Interface name should be instantiated with it, as it is a part of the Interface only.

Why no multiple inheritance in Java?

Hence, Java does not support multiple inheritance because it can lead to increased complexity and ambiguity in case of ‘ Diamond Problem ‘ which means that when classes with same signature in both the parent classes are made and child class when on calling the method makes the compiler cannot determine which class method to be called and this causes diamond problem and gives the compile time Error.

Why is multiple inheritance not allowed in Java?

Multiple Inheritance for classes is not supported in Java, but it does support multiple inheritance for interfaces. Main reason for not allowing multiple inheritance for classes is Deadly diamond of Death pattern( also known as DDD).

Can one interface inherit another interface in Java?

Also, it is possible for a java interface to inherit from another java interface, just like classes can inherit from other classes. You specify inheritance using the extends keyword. Inheritance will be further discussed below. But unlike classes, interfaces can actually inherit from multiple interfaces.

Does Java support Multilevel inheritance?

Java doesn’t support multilevel inheritance. It is achieved through interface. This means that you can’t inherit more than two classes in java directly. Interfaces are similar to classes but it contains abstract variables and methods, which means they are just declared and not defined.