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Java LinkedHashMap keySet() Method with Example

LinkedHashMap Class keySet() method: Here, we are going to learn about the keySet() method of LinkedHashMap Class with its syntax and example.
Submitted by Preeti Jain, on March 09, 2020

LinkedHashMap Class keySet() method

  • keySet() method is available in java.util package.
  • keySet() method is used to get all the existing keys in this LinkedHashMap to be viewed in a Set.
  • keySet() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
  • keySet() method does not throw an exception at the time of returning the key set.

Syntax:

    public Set keySet();

Parameter(s):

  • It does not accept any parameter.

Return value:

The return type of the method is Set, it returns Set view of all the key exists in this LinkedHashMap.

Example:

// Java program to demonstrate the example // of Set keySet() method of LinkedHashMap import java.util.*; public class KeySetOfLinkedHashMap { public static void main(String[] args) { // Instantiates a LinkedHashMap object Map < Integer, String > map = new LinkedHashMap < Integer, String > (); // By using put() method is to add // key-value pairs in a WeakHashMap map.put(10, "C"); map.put(20, "C++"); map.put(50, "JAVA"); map.put(40, "PHP"); map.put(30, "SFDC"); //Display LinkedHashMap System.out.println("LinkedHashMap: " + map); // By using keySet() method is to // return the set of of keys exists // in this LinkedHashMap to be viewed in // a Set Set s = map.keySet(); // Display status System.out.print("map.keySet(): "); System.out.println(s); } }

Output

LinkedHashMap: {10=C, 20=C++, 50=JAVA, 40=PHP, 30=SFDC}
map.keySet(): [10, 20, 50, 40, 30]


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