Berlin Brown and Software Development

Overview - Playing the Game Of Life When most computer users upload a profile image from their desktop to Facebook's website they don't stop to think about the simple binary math rules that are fundamental to most digital devices. We realize that 4 gigabytes of RAM is more memory than 512 megabytes but we don't visualize the logic chips that are involved in an xor $0x100, eax operation for a 32-bit CISC processor. Software developers have to consider memory management or how a computer's operating system loads their programs into memory. They don't normally consider VHDL logic circuit designs, the data paths, arithmetic logic units or the millions of transistors that make up a modern CPU. Those low-level details have been intentionally hidden from the user application developer. The modern CPU may have changed dramatically over the last decade but at the heart of early digital computing were simple Boolean operations. These simple rules were combined togeth...

Here is the implementation of HashMap from OpenJDK 6.  It is interesting how simple it truly is.  Essentially HashMap consists of an array called 'table'.  On the 'put' call, we use the hashcode of the key and then call another hash function, then convert that into an index into the array.  Place the 'value' object at the index array position. OpenJDK HashMap Implementation