Studying Java 8 (see constructor)

Now it's a constructor reference. The method reference in the previous article sensuously specified that the implementation of the functional IF abstract method should be a specific method. Is it an image that you can specify the method and the constructor as specific?

As with the last time, prepare some functional IFs as appropriate. SampleBean is a dedicated return value bean prepared for methodA of SampleFunctionalIF3, and SampleBeanExt is a bean that just extends it and creates a default constructor. getter and setter are omitted.

@FunctionalInterface
public interface SampleFunctionalIF<T> {
	String methodA(T object);
}

@FunctionalInterface
public interface SampleFunctionalIF2 {
	String methodA();
}

@FunctionalInterface
public interface SampleFunctionalIF3 {
	SampleBean methodA(String A, String B);
}

public class SampleBean {

	private String val1;
	private String val2;
}

public class SampleBeanExt extends SampleBean {

	SampleBeanExt(String param1, String param2) {
		this.setVal1(param1);
		this.setVal2(param2);
		System.out.println("SampleBeanExt constructor called");
	}
}

So, the following is trying to execute these.

public class ConstructorRef {
	public static void main(String[] args) {

		//With argument (String)in the case of
		//New String at the timing when the abstract method methodA specified by the functional IF is called("xyz")Is called
		System.out.println("-----Example 1-----");
		SampleFunctionalIF<String> sample = String::new;
		System.out.println(sample.methodA("xyz"));

		//No arguments (String)in the case of
		//New String at the timing when the abstract method methodA specified by the functional IF is called()Is called
		//The size is 0 because it is an empty string
		System.out.println("-----Example 2-----");
		SampleFunctionalIF2 sample2 = String::new;
		String s2 = sample2.methodA();
		System.out.println(s2.length());

		//With 2 arguments
		//At the timing when the abstract method methodA specified by the functional IF is called
		// new SampleBeanExt("hello","world")Is called
		System.out.println("-----Example 3-----");
		SampleFunctionalIF3 sample3 = SampleBeanExt::new;
		SampleBean bean = sample3.methodA("hello", "world");
		System.out.println("1:" + bean.getVal1());
		System.out.println("2:" + bean.getVal2());
	}
}

And the execution result

-----Example 1-----
xyz
-----Example 2-----
0
-----Example 3-----
SampleBeanExt constructor called
1:hello
2:world

It seems like it's just after doing a method reference. However, I can't think of any use for this.