Question 1C What are the outputs of running class TestMap of

Question 1C What are the outputs of running class TestMap of the following code?

public class TestMap {

public static void main(String[] args) {

Map map = new LinkedHashMap<>();

map.put(\"123\", \"John Smith\");

map.put(\"111\", \"George Smith\");

map.put(\"123\", \"Steve Yao\");

map.put(\"222\", \"Steve Yao\");

System.out.println(\"(1) \" + map);

System.out.println(\"(2) \" + new TreeMap(map));

} }

Solution

There is a wrong in Above code line 3 . to correct it , write the argument type inside <>.

The corrected statement is

Map map = new LinkedHashMap<String,String>(); // as in subsequet lines ,map.put() takes two strings as <key,Value> pairs.

Now the output will be:-

System.out.println(\"(1) \" + map); outputs (1) {123=Steve Yao, 111=George Smith, 222=Steve Yao}

Explanation: enties in LinkedHashMap() are retrieve in ind order of insertion.

There are 4 put method, but as the key 123 is entried two times, the one key with 123 with new value=steve Yao will be entered. SO the keys are retrieved in order 123,111,222

System.out.println(\"(2) \"+ new TreeMap(map)); outputs- (2) {111=George Smith, 123=Steve Yao, 222=Steve Yao}

Explanation:Here aTreeMap object is used which abstracts map object. Entries are retrieved from A treeMap object in sorted orderby key.