java easy to use lambda expressions code example

Example 1: how to use lambda in java

StateOwner stateOwner = new StateOwner();

stateOwner.addStateListener(
    (oldState, newState) -> System.out.println("State changed")
);

Example 2: java "->"

interface LambdaFunction {
    void call();
}
class FirstLambda {
    public static void main(String []args) {
        LambdaFunction lambdaFunction = () -> System.out.println("Hello world");
        lambdaFunction.call();
    }
}

Example 3: java "->"

Runnable r = ()-> System.out.print("Run method");

// is equivalent to

Runnable r = new Runnable() {
            @Override
            public void run() {
                System.out.print("Run method");
            }
        };