Core Java Study Guide with Java Fundamentals to Java 25

A Pro study guide on Java: 45 lessons in 9 parts, 7 hands-on Practical use cases. A Pro plan opens every lesson, practice question and Practical.

What you will learn

Language basics - Types and var, operators, if and switch, loops, arrays, and strings in depth, with programs you can edit. (6 lessons)
Objects and classes - Classes and constructors, how the stack and heap work, encapsulation, inheritance, polymorphism, interfaces, and value classes. (7 lessons)
Collections and generics - List, Set, Map, Queue and Deque, generics, iterators and sorting. (5 lessons)
Exceptions - try, catch, finally, try-with-resources, and checked versus unchecked exceptions. (2 lessons)
Lambdas, streams and concurrency - Lambdas, streams, Optional, threads and CompletableFuture, and the java.time API. (5 lessons)
Java 11 - String and file shortcuts, the HTTP Client, var in lambdas and what the platform dropped. (3 lessons)
Java 12 to 17 - Switch expressions, records, sealed classes, instanceof patterns, text blocks, new library methods, and how to move from 11 to 17. (7 lessons)
Java 21 - Pattern matching for switch, record patterns, virtual threads, sequenced collections and handy additions. (5 lessons)
Java 22 to 25 - Unnamed variables, code before super(), compact source files, scoped values, gatherers and platform improvements. (5 lessons)