How can I iterate over a map in Java?

How can I iterate over a map in Java?

You can iterate over a map in Java using several methods, such as using a for-each loop with entrySet(), keySet(), or values(). Which method would you like to know more about?

Can you show me an example using entrySet()?

Sure! Here's an example:

Map<String, Integer> map = new HashMap<>();
map.put("Apple", 1);
map.put("Banana", 2);

for (Map.Entry<String, Integer> entry : map.entrySet()) {
    System.out.println(entry.getKey() + ": " + entry.getValue());
}

This will print each key-value pair in the map.

What about using keySet()?

Using keySet() is also straightforward. Here's an example:

for (String key : map.keySet()) {
    System.out.println(key + ": " + map.get(key));
}

This will achieve the same result by iterating through the keys.

Are there any performance differences between these methods?

Yes, there can be performance differences. Using entrySet() is generally more efficient for large maps because it avoids multiple lookups compared to keySet(). However, for small maps, the difference is negligible.