Welcome to my Java Hash Table tutorial. A Hash Table is a data structure offers fast insertion and searching capabilities. The negative is that they are limited in size because they are based on arrays. They are also hard to order.
People get confused about them because of the Hash Function. A hash function is used to generate a unique key for every item in the array. Since every item is entered using a calculation, this allows you to reverse the calculation to immediately find the proper index. This way you can find items without the need to search through the whole array.