Java collection framework is used to manipulate the collection of the object. Collection framework contains multiple wrapper classes , convenience class , classes for legacy implementation like vector and Hashtable, collection interfaces and etc.
Collection is an interface in the java collection framework. It is divided into two parts −
- Java util collection - It contains classes such as Set , queue , List and etc.
- Java util map - It contains classes such as Map , sortedMap and etc.
On the other hand , Collections is the one the utility class. Main purpose of this class is to provide convenience method to the developers. This class has only static methods that operate on and return collection. The methods of this class all throw a NullPointerException if the collections or class objects provided to them are null.
| Sr. No. | Key | Collection | Collections |
|---|---|---|---|
1 | Basic | It is an interface in Java collection framework | It is a utility class in Collection framework |
2 | Static Methods | It doesn't has all static methods | It has all static method |
3 | Operation | It is used to store list of object in a single object | It is used to operate on collection. |
Example of Collection and Collections
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Main {
public static void main(String[] args) {
// List
List list = new ArrayList();
list.add("HCL");
list.add("DELL");
// Sorting List in ascending order according to the natural ordering
Collections.sort(list);
list.forEach(System.out::println);
}
}