What are the method references in Java?
Method reference is the way in a lambda expression to refer a method without executing it. In the body of a lambda expression, we can able to call another method if they are compatible with a functional interface.
The operator "::" can be used to separate the class name from the method name.
Method reference to a static method
A static method has referred by using the class name. In lambda expression, we can refer to a static method by using the below syntax.
Syntax
Class-name :: Method-name;
Example
interface Test {
void func();
}
class StaticMethodRef {
static void message() {
System.out.println("Welcome to Tutorials Point");
}
}
public class LambdaMethodRefTest1 {
public static void main(String arg[]) {
Test test = StaticMethodRef :: message; // calling using "::" operator
test.func();
}
}Output
Welcome to Tutorials Point
Method reference to an instance method
An instance method has referred by using a lambda expression. We need to refer an instance method, use an instance name instead of a class name. The "::" operator can be used to refer to instance methods also.
Syntax
Instance-name :: Method-name;
Example
interface Test {
void func();
}
class InstanceMethodRef {
void message() {
System.out.println("Welcome to Tutorix");
}
}
public class LambdaMethodRefTest2 {
public static void main(String arg[]) {
InstanceMethodRef ref = new InstanceMethodRef();
Test test = ref :: message; // calling using "::" operator
test.func();
}
}Output
Welcome to Tutorix
Published on 12-Dec-2019 15:09:20
