When you create a HashMap, what the Java virtual machine does is it creates a single-dimensional array to hold all of your data, to hold everything that you want to put into your HashMap. Now, there's ...

This post shows readers how to create an array in Java. Including: Array Lists, multidimensional arrays, maps, and more.

How to add multiple values per key to a Java HashMap. It seems like an oversight for the standard Java API not to have a collection class that allows a key to have multiple values. If this is an ...