Thursday, 14 July 2016

Convert List into Map in Java 8

Convert List<V> into Map<K, V> in Java 8

Sometimes it is necessary to convert a List of Objects to Map in Java 8.
In Java 8 we can simply do this using Collectors class .
Let us look at the following example.

class Employee {
 public String name;
 public int age;

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

 public String getName() {
  return name;

Now we can convert a list of Employee Objects to a Map like this
We will use the names of the Employees as the key of the Map.

List<Employee> empList = Arrays.asList(
                            new Employee("Jim", 18),
                            new Employee("Joe", 25), 
                            new Employee("Harry", 40)
Map<String, Employee> result =
                    .collect(Collectors.toMap(Employee::getName, x -> x));



Joe   =, 
Harry =, 
Jim   =