Java HashMap getOrDefault() Usage and Example

Java HashMap Methods

If the mapping for the specified key is not found in the hash map, the Java HashMap getOrDefault() method will return the specified default value.

Otherwise, the method returns the value corresponding to the specified key.

The syntax of the getOrDefault() method is:

hashmap.get(Object　key,　V　defaultValue)

getOrDefault() parameters

• key -　 To return its mappingValuekey

• defaultValue　 -　 Returns the specified defaultValue if the mapping for the specified key is not found

getOrDefault() returned value

• Returns the value associated with the specified key

• Returns the specified defaultValue if the mapping for the specified key is not found

Example: Java HashMap getOrDefault()

import　java.util.HashMap;
class　Main　{
　　　　public　static　void　main(String[]　args)　{
　　　　　　　　//　Creating　HashMap
　　　　　　　　HashMap<Integer,　String>　numbers　=　new　HashMap<>();
　　　　　　　　//Inserting an entry into the HashMap
　　　　　　　　numbers.put(1,　"Java");
　　　　　　　　numbers.put(2,　"Python");
　　　　　　　　numbers.put(3,　"JavaScript");
　　　　　　　　System.out.println("HashMap:　"　+　numbers);
　　　　　　　　//The key mapping exists in the HashMap
　　　　　　　　String　value1　=　numbers.getOrDefault(1,　"Not　Found");
　　　　　　　　System.out.println("Key"}1Value:　　"　+　value1);
　　　　　　　　//The key mapping does not exist in the HashMap
　　　　　　　　String　value2　=　numbers.getOrDefault(4,　"Not　Found");
　　　　　　　　System.out.println("Key"}4value: "　+　value2);
　　　　}
}

Output Result

HashMap: {1=Java,　2=Python,　3=JavaScript}
key1value: Java
key4value: Not Found

In the above example, we created a hash map named numbers. Note the expression

numbers.getOrDefault(1, "Not Found")

Here,

• 1 -　 to return the key mapping value

• Not Found - If the key does not exist in the hash map, it will return the default value
  

Since the hashmap contains the key mapping1. Therefore, Java will return this value.

But, please note the following expression:

numbers.getOrDefault(4, "Not Found")

Here,

• 4 - to return the key mapping value

• Not Found　 - Default value

Since the hash map does not contain the key4any map. Therefore, it will return the default value Not Found.

Note: We can useHashMap containsKey()Method to check if a specific key exists in the hash map.

Java HashMap Methods