Retrieving elements

To retrieve elements from a Map, you can use any of the following four methods:

• V get(Object K): It returns the value by the provided key, or null if the provided key is not in the map
• V getOrDefault(K, V): It returns the value by the provided key, or the provided (default) value if the provided key is not in the map
• Map.Entry<K,V> entry(K,V): A static method that converts the provided key-value pair into an immutable object of Map.Entry (immutable means it can be read, but cannot be changed)
• Map<K,V> ofEntries(Map.Entry<? extends K,? extends V>... entries): It creates an immutable map based on the provided entries

The following code demonstrates these methods:

Map<Integer, String> map = new HashMap<>();
map.put(1, null);
map.put(2, "s2");
map.put(3, "s3");

System.out.println(map.get(2));                 //prints: s2
System.out.println(map.getOrDefault(2, "s4"));  //prints: s2
System.out.println(map.getOrDefault(4, "s4"));  //prints: s4

Map.Entry<Integer, String> entry = Map.entry(42, "s42");
System.out.println(entry);      //prints: 42=s42

Map<Integer, String> entries = 
                Map.ofEntries(entry, Map.entry(43, "s43"));   
System.out.println(entries);   //prints: {42=s42, 43=s43}

And it is always possible to retrieve elements of a map by iterating, as we have described in the subsection Iterate and stream.