What is the difference between entrySet and keySet in Java?

In Java, the Map interface has two methods that can return collections of keys and values: entrySet() and keySet().

1. The entrySet() method returns a Set collection containing key-value pairs (Entry objects) from a Map. Each Entry object includes a key and its corresponding value. This collection can be accessed and manipulated by iterating through each Entry object.
2. The keySet() method returns a Set collection containing all the keys in the Map. This collection can be accessed and used to operate on the corresponding values by iterating through each key.

Therefore, the entrySet() method returns a collection of key-value pairs, while the keySet() method returns a collection of keys. As a result, the entrySet() method is often used in scenarios where both keys and values need to be accessed simultaneously, while the keySet() method is commonly used in scenarios where only keys need to be accessed.