Reddit reviews Introduction to Algorithms (Eastern Economy Edition)

A hash table is not a "Java thing", it's a term for a fundamental concept and data structure in computing.

For example, C#/.NET has a Hashtable class, and the C#/.NET docs for Dictionary describe it as follows:

> The Dictionary<TKey, TValue> generic class provides a mapping from a set of keys to a set of values. Each addition to the dictionary consists of a value and its associated key. Retrieving a value by using its key is very fast, close to O(1), because the Dictionary<TKey, TValue> class is implemented as a hash table.

The reason that both the Java and C# docs use the term "hash table", and say that HashMap and Dictionary are implemented as hash tables, is because "hash table" is the name for the concept they're both using. Pretty much all programming languages and operating systems use this concept heavily, as do databases, caching systems, and other kinds of software. Next to arrays, it's one of the most commonly used data structures for collections of values.

You should check out a book like Introduction to Algorithms. It will put your programming-language specific knowledge in a broader perspective.

Free textbook online $30 paperback
Https://Opendatastructures.org

Introduction to Algorithms https://www.amazon.ca/dp/8120340078/ref=cm_sw_r_cp_apa_i_GKcwDbNJ7GDJ2

Design Patterns https://www.amazon.ca/dp/9332555400/ref=cm_sw_r_cp_apa_i_sMcwDbY6S7ESR

These will cover major computer science concepts but as for actual programming theres books all over the place but they're nowhere near as useful as actually just getting in there and writing some code.
You can start with books like "Thinking Like A Programmer".
Just understand that programming is a tool you should get used to handling regardless of the form and the overarching principals of good software design is what computer science is really about.