About Question enthuware.ocajp.i.v8.2.1478 :
Posted: Tue Jan 19, 2016 4:51 pm
Hello,
This question discusses the usage of super with interfaces.
In Java 8 has been added the following:
X.super.m(...)
where X is an interface whose method m you want to call from some class.
So if your class TestClass implements interface B and you want to use the default method hello from this interface:
Also it is possible from an interface to invoke default method implemented in a super interface:
This question discusses the usage of super with interfaces.
I just wanted to add some additional information in this concern:super.methodName(...) is a valid way to invoke a super class's method from anywhere within a subclass's method. But it works only for classes. You cannot invoke the interface's default method using this technique. In fact, if a class (or an interface) overrides a default method of an interface, there is no way to invoke that default method from that class (or interface).
In Java 8 has been added the following:
X.super.m(...)
where X is an interface whose method m you want to call from some class.
So if your class TestClass implements interface B and you want to use the default method hello from this interface:
Code: Select all
class TestClass implements A {
public static void main(String... args) {
new TestClass().hello(); // Will print "In interface B:hello"
}
public void hello() {
A.super.hello();
}
}
interface A {
default void hello() {
System.out.println("In interface B:hello");
}
} Also it is possible from an interface to invoke default method implemented in a super interface:
Code: Select all
interface A {
default void hello() {
System.out.println("In interface B:hello");
}
}
interface B extends A {
default void hello() {
A.super.hello();
}
}
class TestClass implements B,A {
public static void main(String... args) {
new TestClass().hello(); // Will print "In interface B:hello"
}
public void hello() {
B.super.hello();
//in this case we cannot call A.super.hello because the most specific direct super type is required to be used!
}
}