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Conversion of Java Maps to List
At first, let us create a Java Map and initialize −
Map<Integer, String> map = new HashMap<>(); map.put(1, "Tom"); map.put(2, "John"); map.put(3, "Kevin"); map.put(4, "Jacob"); map.put(5, "Ryan");
Now, convert the Map to List −
ArrayList<Integer> key = new ArrayList<Integer>(map.keySet()); ArrayList<String> value = new ArrayList<String>(map.values());
Example
Following is the program to convert Maps to List in Java −
import java.util.HashMap;
import java.util.ArrayList;
import java.util.Map;
public class Demo {
public static void main(String args[]) {
Map<Integer, String> map = new HashMap<>();
map.put(1, "Tom");
map.put(2, "John");
map.put(3, "Kevin");
map.put(4, "Jacob");
map.put(5, "Ryan");
map.put(6, "Bradley");
map.put(7, "Andy");
map.put(8, "Tim");
System.out.println("HashMap = " + map);
ArrayList<Integer> key = new ArrayList<Integer>(map.keySet());
ArrayList<String> value = new ArrayList<String>(map.values());
System.out.println("
List (Map Keys) = "+key);
System.out.println("List (Map Values) = "+value);
}
}Output
HashMap = {1=Tom, 2=John, 3=Kevin, 4=Jacob, 5=Ryan, 6=Bradley, 7=Andy, 8=Tim}
List (Map Keys) = [1, 2, 3, 4, 5, 6, 7, 8]
List (Map Values) = [Tom, John, Kevin, Jacob, Ryan, Bradley, Andy, Tim]
Updated on: 25-Sep-2019
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