Java Collection How to - Create an unmodifiable map

Question

We would like to know how to create an unmodifiable map.

Answer

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/*www. ja  va 2s  .  c o  m*/
public class Main {

  public static void main(String[] args) {
    Map<String, String> map = getMap();
    map.put("a", "b");
  }

  public static final Map<String, String> getMap() {
    Map<String, String> map = new HashMap<String, String>();
    map.put("x", "y");
    return Collections.unmodifiableMap(map);
  }
}

The code above generates the following result.