如何将Lambda转换为简单的Java函数

Question

I am trying to understand a program in java which has used lambda to return object into the reference variable of an interface. I want to convert lambda into simple java function, but not sure how to do it.

The program is as follows:-

public abstract class Performance implements Serializable
{ 
Iterface_name vehicle =(Iterface_name & Serializable) () ->{return new Object();};
Object speed() 
{
    return vehicle.speed();
}
}

The interface is as follows:-

public interface Iterface_name 
{
Object speed();
}

How to convert this program into simple java program without use of lambda for learning. Please help.

Answer 1

You could replace lambda expression with your own implementation of Iterface_name interface.

class Interface_name_impl implements Iterface_name {
    @Override
    public Object speed() {
        return new Object();
    }
}

Subsequently, you can replace your statement that uses lambda expression with

Iterface_name vehicle = new Interface_name_impl();

You can even use anonymous classes with out explicitly have the above class that implements Iterface_name

Iterface_name vehicle1 = new Iterface_name() {
    @Override
    public Object speed() {
        return new Object();
    }
};

On a different note, you could even simply your lambda usage from

Iterface_name vehicle =(Iterface_name & Serializable) () ->{return new Object();};

to

Iterface_name vehicle = () -> new Object();

or even shorter version is

Iterface_name vehicle = Object::new;

In case, you want to understand how lambdas are implemented internally by the compiler you can go through Java-8-Lambdas-A-Peek-Under-the-Hood

Answer 2

Delete the field entirely. This is the same:

public abstract class Performance implements {
    Object speed() {
        return new Object();
    }
}