Java Collection Tutorial - Java Map.containsKey(Object key)

• Back to Map  ↑

Syntax

Map.containsKey(Object key) has the following syntax.

boolean containsKey(Object key)

Example

In the following code shows how to use Map.containsKey(Object key) method.

 //w  ww . jav a  2  s .c  o m
import java.util.HashMap;
import java.util.Map;

public class Main{
  public static void main(String[] a) {

    Map<String,String> map = new HashMap<String,String>();
    map.put("key1", "value1");
    map.put("key2", "value2");
    map.put("key3", "value3");

    System.out.println(map.get("key2"));
    System.out.println(map.containsKey("key2"));
    System.out.println(map.containsKey("key4"));
  }
}
  

The code above generates the following result.

• Back to Map  ↑