How to Print HashMap in Java

Hello Guys,

How to Print HashMap is very common and frequently ask question now a days for testing programming skills in Java.

So,lets try to understand the  program given below.


import java.util.HashMap;
import java.util.Set;


public class Test extends Thread{

public static void main(String[] args) {
//Creating HashMap key and value as String.
HashMap<String, String> st = new HashMap<String, String>();
//Putting some key and value in Map

st.put("K1", "V1");
st.put("K2", "V2");
st.put("K3", "V3");
st.put("K4", "V4");
st.put("K5", "V5");

//Now iterate or loop Map by using KeySet method of Map
for(String name: st.keySet()){

String key= name.toString();
//Here we are calling get method of Map class by passing key which is we got from KeySet()
String value= st.get(name).toString();
System.out.println("Key:- "+ key +"value:- "+ value );
}
}
}
note:-
1)KeySet returns set view of the keys contained in map.
2)Changes to map will reflect to set and vice-versa also possible.

Its very simple Program and can be use by beginners who just started learning java and collection.

Any comment or Suggestion is most welcome!


Thanks,
Vikas