HashMaps

 

Today I read an article on coding-geek.com about HashMaps. I have used HashMaps before in Data Structures as well as Unix systems and have found them to be a very resourceful way to store and retrieve data. Most developers know about HashMaps but don’t completely understand how they work, in todays blog we will be cover HashMaps in JAVA.

HashMaps have an inner class called an Entry Class which holds the key, values and will return a value at the end. Two important main methods in the class are put() and get(). put() associates the specified value with the specified key in the map, it checks if the key given is null or not. If the given key is null, it will be stored in the zero position. The next internal part of the put method is that it fits the values inside of the limits of the array. The get() method is very similar to the put method but instead of storing, it returns a value. Get() gets the hashcode of the main object and finds the location of it in the array. If the right value is discovered, then it returns the value but if it cannot find it then it returns null. Put() and get() are two major internal parts of HashMaps and looking back at some of my old projects with HashMaps I now fully understand what is going on internally when I execute the program. I will use HashMaps more frequently in my projects now and I hope that after reading this you will be able to understand HashMaps better and will be able to give them a shot.

Source: http://coding-geek.com/how-does-a-hashmap-work-in-java/

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