Functional Interface call for a new Instance

Question

I need to write a functional interface call for a new instance of a dynamic object.

Classic way if I would know the class:

() -> new DefinedClass()

But I don't know the exact class. I only have the Class Object of the Class I try to instantiate.

Thx for help!

Do you mean? `Class clazz = ...; Object obj = clazz.newInstance()`? — Eran, Feb 27 '20 at 09:18
Does this answer your question? [instantiate class from class object](https://stackoverflow.com/questions/3036777/instantiate-class-from-class-object) — Torben, Feb 27 '20 at 09:23
And why wouldn't newInstance() work? You're kinda supposed to explain yourself without being asked — kumesana, Feb 27 '20 at 09:27
Because the IDE tells me, "The target type of this expression must be a functional interface" when I use newInstance() — PunkPengu, Feb 27 '20 at 09:51
Its a Spring Boot Application ``` this.context.registerBean(beanInterface, bean.newInstance()); ``` context is GenericWebApplicationContext — PunkPengu, Feb 27 '20 at 12:25
`registerBean` has lots of overloads, including one where you just need to pass constructor parameters (but not call the constructor yourself). — Klitos Kyriacou, Feb 27 '20 at 13:50

score 2 · Answer 1 · answered Feb 27 '20 at 09:28

package test;

import java.util.stream.Stream;

public class Test {
    public static void main(String[] args) {
        Stream.of(Test.class)
                .map(c -> {
                    try {
                        return c.newInstance();
                    } catch (IllegalAccessException | InstantiationException e) {
                        throw new RuntimeException(e);
                    }
                })
                .forEach(System.out::println);
    }

    @Override
    public String toString() {
        return "Test";
    }
}

Functional Interface call for a new Instance

1 Answers1