Collections checkedList() method in Java with Examples

The checkedList() method of java.util.Collections class is used to return a dynamically typesafe view of the specified list.

The returned list will be serializable if the specified list is serializable.

Since null is considered to be a value of any reference type, the returned list permits insertion of null elements whenever the backing list does.

Syntax:

public static  List
    checkedList(List list, Class type)

Parameters: This method takes the following arguments as a parameters:

list – the list for which a dynamically typesafe view is to be returned
type – the type of element that list is permitted to hold

Return Value: This method returns a dynamically typesafe view of the specified list

Below are the examples to illustrate the checkedList() method

Example 1:

// Java program to demonstrate 
// checkedList() method 
// for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // creating object of List<String> 
            List<String> arlst = new ArrayList<String>(); 
  
            // Adding element to arlst 
            arlst.add("A"); 
            arlst.add("B"); 
            arlst.add("C"); 
            arlst.add("TajMahal"); 
  
            // printing the arrlist 
            System.out.println("List: " + arlst); 
  
            // create typesafe view of the specified list 
            List<String> 
                tslst = Collections 
                            .checkedList(arlst, String.class); 
  
            // printing the arrlist after operation 
            System.out.println("Typesafe view of List: " + tslst); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
} 

Output:

List: [A, B, C, TajMahal]
Typesafe view of List: [A, B, C, TajMahal]

Example 2:

// Java program to demonstrate 
// checkedList() method 
// for Integer value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
  
        try { 
  
            // creating object of List<Integer> 
            List<Integer> arlst = new ArrayList<Integer>(); 
  
            // Adding element to arlst 
            arlst.add(20); 
            arlst.add(30); 
            arlst.add(40); 
            arlst.add(50); 
  
            // printing the arrlist 
            System.out.println("List: " + arlst); 
  
            // create typesafe view of the specified list 
            List<Integer> 
                tslst = Collections 
                            .checkedList(arlst, Integer.class); 
  
            // printing the arrlist after operation 
            System.out.println("Typesafe view of List: " + tslst); 
        } 
  
        catch (IllegalArgumentException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
} 

Output:

List: [20, 30, 40, 50]
Typesafe view of List: [20, 30, 40, 50]

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