java 8 play

Main.java

package test;

import java.util.ArrayList;
import java.util.List;
import java.util.function.Predicate;
import java.util.stream.Collectors;

public class Main {

        public static void main(String[] args) {

                List<Employee> list = new ArrayList<>();
                list.add(new Employee(22, "bob"));
                list.add(new Employee(20, "bob2"));
                list.add(new Employee(42, "bob3"));
                list.add(new Employee(32, "bob4"));

                Predicate<Employee> a = Employee::isOld;

                List<String> result = list.stream().filter(Employee::isOld)
                                .map(Employee::getName).collect(Collectors.toList());

                //  VS

                List<String> names = new ArrayList<>();
                for (Employee e : list) {
                        if (e.isOld()) {
                                names.add(e.getName());
                        }
                }

        }

        public static class Employee {

                private int age;
                private String name;

                public Employee(int age, String name) {
                        super();
                        this.age = age;
                        this.name = name;
                }

                public String getName() {
                        return name;
                }

                public int getAge() {
                        return age;
                }

                public boolean isOld() {
                        return age > 20;
                }
        }

}