Home  >  Java 8

Java Map getOrDefault() Example

By Arvind Rai, February 12, 2020
The getOrDefault is the default method of java.util.Map and has been introduced in Java 8. The getOrDefault method returns the value for the given key and if there is no value associated with that key then the specified default value is returned. Find the method signature.
default V getOrDefault(Object key, V defaultValue) 
key for which the value is to obtain.
defaultValue is the default value.
Return value is a value associated with key and if absent then default value is the return value.

Example-1

In this example, we are using HashMap.
GetOrDefault1.java
import java.util.HashMap;
import java.util.Map;

public class GetOrDefault1 {
  public static void main(String[] args) {
     Map<Integer, String> studentMap = new HashMap<>();
     studentMap.put(101, "Mahesh");
     studentMap.put(102, "Suresh");
     studentMap.put(103, "Krishna");
     
     String defaultValue = "No Student";
     String stdName = studentMap.getOrDefault(102, defaultValue);
     System.out.println(stdName);
     
     stdName = studentMap.getOrDefault(104, defaultValue);
     System.out.println(stdName);
     
     stdName = studentMap.getOrDefault(105, defaultValue);
     System.out.println(stdName);     
     
  }
} 
Output
Suresh
No Student
No Student 
As for key 102, there is associated value in Map, so we get that value. For the key 104 and 105, there is no associated value and hence we will get specified default value.

Example-2

In this example, we are using LinkedHashMap.
GetOrDefault2.java
import java.util.LinkedHashMap;
import java.util.Map;

public class GetOrDefault2 {
  public static void main(String[] args) {
     Map<Integer, Integer> numberMap = new LinkedHashMap<>();
     numberMap.put(1, 100);
     numberMap.put(2, 200);
     numberMap.put(3, 300);
     
     Integer defaultValue = 0;
     Integer val = numberMap.getOrDefault(2, defaultValue);
     System.out.println(val);
     
     val = numberMap.getOrDefault(6, defaultValue);
     System.out.println(val);
     
     val = numberMap.getOrDefault(7, defaultValue);
     System.out.println(val);     
     
  }
} 
Output
200
0
0 

Example-3

In this example, we are using TreeMap.
GetOrDefault3.java
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

public class GetOrDefault3 {
  public static void main(String[] args) {
     Map<String, List<String>> treeMap = new TreeMap<>();
     treeMap.put("color", Arrays.asList("Orange", "Yellow"));
     treeMap.put("game", Arrays.asList("Cricket", "Hockey"));
     
     List<String> defaultValue = new ArrayList<>();
     List<String> val = treeMap.getOrDefault("game", defaultValue);
     System.out.println(val);
     
     val = treeMap.getOrDefault("city", defaultValue);
     System.out.println(val);
  }
} 
Output
[Cricket, Hockey]
[] 

Reference

Java doc: Map
POSTED BY
ARVIND RAI
ARVIND RAI








©2020 concretepage.com | Privacy Policy | Contact Us