CCNA, CCNP, MCSA, CCNA Final Exam, All Answer Test Module With 100/100

Comparison of HashMap and Hashtable source code in jdk 1.6, I saw below codes inside HashMap

Lately I had an issue with an array that contained some hundred thousands of values and the only thing I wanted to do was to check whether a value was already present. In my case this were IPs from a webserver log. So basically something like:

Is there anyway I can print out the Keys with the values that had collisions ? If a key has two values I want to be able to print out those values how can I do that I am inside the hash map class and making modification to it.