A project from JetBrains Academy:
Files come in all possible formats: we usually see it specified in their names. Even if the file type was manual changed or even removed, information about the type is always contained within the file. And in this project, you will write a tool that will extract this info to determine the type of the file. You’ll try out different algorithms to solve this problem, and will see for yourself how using different algorithms will change the speed of the tool.
Figure out multithreading and learn to work with Knuth-Morris-Pratt algorithm, a must-know for every developer. Consider Rabin-Karp algorithm the icing on the cake. Good luck!