How to convert a list with properties to a another list the java 8 way?

Question

There is a List A with property Developer. Developer schema likes that:

@Getter @Setter public class Developer {     private String name;     private int age;      public Developer(String name, int age) {         this.name = name;         this.age = age;     }      public Developer name(String name) {         this.name = name;         return this;     }      public Developer name(int age) {         this.age = age;         return this;     } } 

List A with properties:

List<Developer> A = ImmutableList.of(new Developer("Ivan", 25), new Developer("Curry", 28)); 

It is demanded to convert List A to List B which with property ProductManager and the properties is same as the ones of List A.

@Getter @Setter public class ProductManager {     private String name;     private int age;      public ProductManager(String name, int age) {         this.name = name;         this.age = age;     }      public ProductManager name(String name) {         this.name = name;         return this;     }      public ProductManager name(int age) {         this.age = age;         return this;     } } 

In the old days, we would write codes like:

public List<ProductManager> convert() {     List<ProductManager> pros = new ArrayList<>();     for (Developer dev: A) {         ProductManager manager = new ProductManager();         manager.setName(dev.getName());         manager.setAge(dev.getAge());         pros.add(manager);     }     return pros; } 

How could we write the above in a more elegant and brief manner with Java 8?

Answer 1

you will have to use something like below :

List<ProductManager> B = A.stream()         .map(developer -> new ProductManager(developer.getName(), developer.getAge()))         .collect(Collectors.toList()); 

// for large # of properties assuming the attributes have similar names //other wise with different names refer this

List<ProductManager> B = A.stream().map(developer -> {             ProductManager productManager = new ProductManager();             try {                 PropertyUtils.copyProperties(productManager, developer);             } catch (Exception ex) {                 ex.printStackTrace();             }             return productManager;         }).collect(Collectors.toList());          B.forEach(System.out::println); 

Answer 2

Probably, like this:

List<ProductManager> B = A.stream()         .map(developer -> new ProductManager(developer.name, developer.age))         .collect(Collectors.toList());