A graph provides a very attractive solution when you want to model real-world data. As they are more flexible than RDBMS, they offer an intuitive approach and are practically relevant to the way we think of stuff. The graph world revolves around several featured algorithms that are used to process graphs and for route calculation, detection of loops, calculation of the shortest path, subgraph and pattern matching being a few of them. Although you can implement your own collection of algorithms and tweaks, Neo4j also includes a set of predefined algorithms that you use most for rapid application development, even for scenarios that involve large volumes of data. They are packaged in a library called the graphalgo that you can use directly in your Java code fragments. The REST API also exposes a few of these algorithms such as dijkstra's and A* to be used with requests sent to the REST server. The graphalgo interfaces can be accessed and used in your programs using methods...