Iterating a HashMap

We know that, Java HashMap class implements the map interface by using a hashtable. It inherits AbstractMap class and implements Map interface.
The important points about Java HashMap class are:

• A HashMap contains values based on the key.
• It contains only unique elements.
• It may have one null key and multiple null values.
• It maintains no order.

Many times we have to iterate hash map for key or value or both key&value.
Here is code block to iterate for the same...

If you're only interested in the keys, you can iterate through the keySet() of the map:

Map<String, Object> map = ...;

for (String key : map.keySet()) {
    // ...
}

If you only need the values, use values():

for (Object value : map.values()) {
    // ...
}

Finally, if you want both the key and value, use entrySet():

for (Map.Entry<String, Object> entry : map.entrySet()) {
    String key = entry.getKey();
    Object value = entry.getValue();
    // ...
}

Have Fun!!!

Happy Coding!!!