Write a Java program to get keys from a HashMap collection

This Java program demonstrates how to get the keys of a HashMap collection using the keySet() method. Here is a step-by-step explanation of the program:

First, we import the java.util.* package, which includes the HashMap and Set classes that we'll be using.
We define a new class called Get_Keys.
Inside the main method, we create a new HashMap object called stu that maps integer keys to string values.
We use the put method to add key-value pairs to the stu HashMap.
We create a new Set object called keys and use the keySet() method to retrieve the set of keys from the stu HashMap. The keySet() method returns a view of the keys in the HashMap.
We use a for loop to iterate through the set of keys in keys.
Inside the loop, we use the println() method to print each key to the console.
Finally, we close the main method and the Get_Keys class.

Source Code

import java.util.*;
public class Get_Keys
{
	public static void main(String[] args)
	{
		HashMap < Integer, String > stu = new HashMap < > ();
		stu.put(101, "Kim");
		stu.put(102, "Arun");
		stu.put(103, "Deepika");
		stu.put(104, "Ramesh");
		stu.put(105, "Joes");
		stu.put(106, "Abi");
		stu.put(107, "John");
		stu.put(108, "Vijay");
		stu.put(109, "Suga");
		stu.put(110, "Siva");
		Set < Integer > keys = stu.keySet();
 
		System.out.println("Keys from a HashMap Collection ..");
		for (Integer key: keys)
		{
			System.out.println(key);
		}
	}
}

Output

Keys from a HashMap Collection ..
101
102
103
104
105
106
107
108
109
110

Write a Java program to get keys from a HashMap collection

Source Code

Output

Example Programs

HashMap Programs in Java