Java Collections checkedCollection() Method

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Description

The Java Collections checkedCollection(Collection<E>, Class<E>) method is used to get a dynamically typesafe view of the specified collection.

Declaration

Following is the declaration for java.util.Collections.checkedCollection() method.

public static <E> Collection<E> checkedCollection(Collection<E> c,Class<E> type)

Parameters

• c − This is the collection for which a dynamically typesafe view is to be returned.

• type − This is the type of element that c is permitted to hold.

Return Value

The method call returns a dynamically typesafe view of the specified collection.

Exception

NA

Getting a TypeSafe View of Collection of Integers Example

The following example shows the usage of Java Collection checkedCollection(Collection,Class ) method to get a typesafe view of collection of integers. We've created a List object with some integers, printed the original list. Using checkedCollection(Collection, Integer) method, we're getting a collection of Integer and then it is printed.

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

public class CollectionsDemo {

   public static void main(String[] args) {
      List<Integer> list = new ArrayList<>(Arrays.asList(1,2,3,4,5));

      System.out.println("Initial collection value: " + list);

      Collection<Integer> safeList = Collections.checkedCollection(list, Integer.class);
      System.out.println("Typesafe View: "+safeList);
   }
}

Output

Let us compile and run the above program, this will produce the following result.

Initial collection value: [1, 2, 3, 4, 5]
Typesafe View: [1, 2, 3, 4, 5]

Getting a TypeSafe View of Collection of Strings Example

The following example shows the usage of Java Collection checkedCollection(Collection,Class ) method to get a typesafe view of collection of strings. We've created a List object with some strings, printed the original list. Using checkedCollection(Collection, String) method, we're getting a collection of String and then it is printed.

package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

public class CollectionsDemo {

   public static void main(String[] args) {
      List<String> list = new ArrayList<>(Arrays.asList("Welcome","to","Tutorialspoint"));

      System.out.println("Initial collection value: " + list);

      Collection<String> safeList = Collections.checkedCollection(list, String.class);
      System.out.println("Typesafe View: "+safeList);
   }
}

Output

Let us compile and run the above program, this will produce the following result.

Initial collection value: [Welcome, to, Tutorialspoint]
Typesafe View: [Welcome, to, Tutorialspoint]