Java 8 - Lambda Expression for Collections:

Lambda Expression for Collections:

• Using Lambda expression we can sort the collections datas.

ArrayList<Integer> l = new ArrayList<>();

l.add(10);

l.add(20);

l.add(5);

l.add(7);

l.add(25);

Java 7:

Class MyCompartor implements comparator<Interger>{

public int compare(Interger I1, Integer I2){

return (I1 > I2)?-1: (I1 < I2)?1:0);

}

}

Collections.sort(l, new MyComparator());

Java 8:

Collections.sort(l, (I1, I2 ) -> (I1 > I2)?-1: (I1 < I2)?1:0);

TreeSet<Integer> t = new TreeSet<>(); -> Default Natural Sorting.

TreeSet<Integer> t = new TreeSet<>( (I1, I2) -> (I1 > I2)?-1:(I1 < I2)?1:0 );

Below is the example to sort the custom class ,

Class Employee {

private int id;

private String name;

Employee(int id, String name){

this.id = id;

this.name =name;

}

}

Java 8 :

Class Test{

public static void main(String args[]){

ArrayList<Employee> l = new ArrayList<>();

l.add(new Employee(100,"Karthick"));

l.add(new Employee(150,"Suresh"));

l.add(new Employee(110,"Rajesh"));

Collections.sort(l, (e1, e2) -> (e1 < e2)?-1: (e1 > e2)?1:0);

}

}