Lambda Expression Example. Java 8

App.java

import com.sun.xml.internal.messaging.saaj.packaging.mime.util.BEncoderStream;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by iliesa on 22.09.2016.
 */
public class App {

    private List<Integer> numbers = new ArrayList<>();
    public App(){
        for (int i = 0; i < 10; i++){
            numbers.add(i);
        }
        List<Integer> expectedNumbers = findNumber(numbers,  number -> number > 4 && number < 7);
        for(int i: expectedNumbers){
            System.out.println(i);
        }
    }
    List<Integer> findNumber(List<Integer>  numbers, NumberPredicat p){
            List<Integer> result = new ArrayList<>();
            for (Integer number : numbers){
                if(p.test(number)){
                    result.add(number);
                }
            }
            return  result;
    }
    public static void main(String[] args) {
        new App();
    }
}

NumberPredicat.java

/**
 * Created by iliesa on 22.09.2016.
 */

@FunctionalInterface
public interface NumberPredicat {
    boolean test(int number);
}