Map.keySet() has the following syntax.
Set < K > keySet()
In the following code shows how to use Map.keySet() method.
//from w w w . j a v a2 s . co m import java.util.HashMap; import java.util.Iterator; import java.util.Map; public class Main { public static void main(String[] argv) { Map map = new HashMap(); map.put("Adobe", "Mountain View, CA"); map.put("IBM", "White Plains, NY"); map.put("Learning Tree", "Los Angeles, CA"); Iterator k = map.keySet().iterator(); while (k.hasNext()) { String key = (String) k.next(); System.out.println("Key " + key + "; Value " + (String) map.get(key)); } } }
The output: