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javalambdasupplier

How can we create an instance for Supplier as it is an Interface?

I am trying to understand Supplier interface. I understand that it can return an object if we invoke its get() method. However, in the following example:

public class SupplierExample {

    public static void main(String[] args) {
        Supplier<String> s = new Supplier<String>() {
            public String get() {
                return "test";
            }
        };

        System.out.println(s.get());
    }
}

I am not able to understand how we can instantiate an object (s in above exaple) from an interface. Please advise.

Solution

  • This snippet contains an anonymous class instance, which implements the Supplier<String> interface.

    It implements the only method of that interface with:

    public String get() {
    return "test";
}

    which returns the String "test".

    Therefore, s.get() returns the String "test".