liviutudor

public Collection<Double> extract(Collection<Employee> collection) {
    return collection.stream().map(c -> c.salary).collect(Collectors.toList());
}

liviutudor

public Optional<Double> max(Collection<Double> collection) {
    if (collection == null || collection.isEmpty()) return Optional.empty();
    Iterator<Double> iter = collection.iterator();

    Double max = iter.next();
    while (iter.hasNext()) {
        Double n = iter.next();
        if (n > max) max = n;
    }

liviutudor

public Optional<Double> findExtractAndMax(Collection<Employee> collection, String name) {
    return collection.stream().filter(e -> e.firstName.equals(name)).map(e -> e.salary).max((a, b) -> (int) Math.signum(a - b));
}

//usage
double sal = findExtractAndMax(collection, "Bob");

liviutudor

@GET
public Response processRequest( @QueryParam("id")String id, @QueryParam("userId")String userId ) {
  Record retrieve = database.retrieveRecord(id);
  logger.writeEntryFor( id, userId );
  UserProfile profile = userStore.retrieve(userId);
  generateAdResponse(retrieve, profile);
}

liviutudor

@GET
public Observable<Response> processRequest( @QueryParam("id")String id, @QueryParam("userId")String userId ) {
  return Observable.zip(
    Observable.fromCallable(() -> database.retrieveRecord(id)),
    Observable.fromCallable(() -> userStore.retrieve(userId)),
    Observable.fromCallable(() -> logger.writeEntryFor(id, userId)),
    this::generateAdResponse
  );
}

liviutudor

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;

public class JacksonBean {
  private final int value;
  private final String another;
  
  @JsonCreator
  public JacksonBean(@JsonProperty("value") int value, @JsonProperty("another") String another) {
    this.value = value;

liviutudor

import java.beans.ConstructorProperties;

public class JacksonBean {
  private final int value;
  private final String another;
  
  @ConstructorProperties({"value", "another"})
  public JacksonBean(int value, String another) {
    this.value = value;
    this.another = another;

liviutudor

import groovy.transform.Sortable
import groovy.transform.TupleConstructor

@Sortable
@TupleConstructor
class BeanOne {
    String firstName
    String familyName

    public String getFullName() {

liviutudor

import groovy.transform.Sortable
import groovy.transform.TupleConstructor

@Sortable
@TupleConstructor
class BeanTwo {
    int yob

    public int getAge() {
        new Date().year - yob

liviutudor

class DelegationBean {
    @Delegate
    BeanOne person

    @Delegate
    BeanTwo dateOfBirth
    
    static void main(String... args) {
        DelegationBean one = new DelegationBean(person: new BeanOne("Liviu", "Tudor"), dateOfBirth: new BeanTwo(yob: 1975))
        DelegationBean two = new DelegationBean(person: new BeanOne("William", "Shakespeare"), dateOfBirth: new BeanTwo(yob: 1564))