Java Stream reduce and sum via lambda expression
import java.util.Arrays; import java.util.List; public class Main { public static void main(String[] args) { Language[] langArray = { // new Language("CSS", 55555), // new Language("HTML", 66666), // new Language("Java", 44444.5), // new Language("Javascript", 77777.77), // new Language("C++", 88888), // new Language("C", 33333), // new Language("SQL", 99999.4) };// List<Language> langList = Arrays.asList(langArray); langList.stream().forEach(System.out::println); double sum = langList .stream()// w ww . j av a2s. co m .reduce( 0.0, (Double partialSum, Language p) -> { double accumulated = partialSum + p.getSalary(); return accumulated; }, (a, b) -> { double combined = a + b; return combined; }); System.out.println(sum); } } class Language { private String firstName; private double salary; public Language(String firstName, double salary) { this.firstName = firstName; this.salary = salary; } public String getFirstName() { return firstName; } public double getSalary() { return salary; } @Override public String toString() { return String.format("%-20s %8.2f", getFirstName(), getSalary()); } }