java hashMap<Integer,String> collision

I'm sorry if this question was already asked, but i don't fine an answer to my question. I'm working on HashMap i put two values (7,"value test 1") (7,"value test 2) According to the specification java API HashMap put the first values is replaced by the second .

My question is when comes the resolution of collision ? why my second value is not store in linkedList or store in another place in the hashMap ? Is it due to the equals or hascode method ??

Best Regards

Solution

This has nothing to do with hash collision. Hash collisions (ie., keys with the same hashcode()) are handled correctly by the HashMap. In your example, both keys are equal (ie., 7.equals(7) == true), so the old value is replaced.

In the following example

Map<Integer, String> map = new HashMap<>();
map.put(7, "value 1");
map.put(7, "value 2");
System.out.println(map.get(7));

what would you expect in the last line to happen?