Java Coding Practice Problems

Last Updated : 11 Aug, 2025

Java coding practice problems help learners and professionals improve their programming skills through real-world challenges, covering topics like data structures, algorithms, and object-oriented concepts.

Fundamentals – The basic building blocks of the Java language, including how to write and run a program, use variables to store data, apply operators for calculations, and control program flow with decisions (if/else) and loops.
Methods – Small sections of code designed to perform a specific task. Methods make code reusable, easier to read, and maintain. You pass inputs (parameters) and get results (return values).
Arrays – A way to store multiple values of the same type in one container. Arrays keep items in order and let you access them using an index number.
Strings – Special objects in Java that represent text. Strings store characters and come with built-in tools for comparing, joining, and modifying text.
OOPs (Object-Oriented Programming) – A style of programming where you model real-world things as objects. These objects have properties (fields) and actions (methods), and you can organize them using concepts like inheritance, polymorphism, abstraction, and encapsulation.
Sorting and Searching Algorithms – Step-by-step methods for arranging data (like numbers or words) in order or finding a specific item quickly. Examples include quicksort, mergesort, and binary search.
Collections – A set of ready-made classes in Java for storing and managing groups of objects, like lists, sets, and maps, without having to build your own data structures from scratch.
Stream & Lambda Expressions – Modern Java features for processing data in a clean, functional style. Streams let you work with collections in a flow-based way, and lambdas are short, inline functions that make code more concise.