In this chapter you’ll dive into the rich toolbox the JDK provides so you don’t have to reinvent the wheel. You’ll see how Java makes everyday tasks—working with text, reading or writing files, managing groups of data, and coordinating multiple threads—straightforward and powerful.

You’ll begin by exploring the world of String handling, from simple concatenation and searching to more advanced text processing with regular expressions. Next, you’ll learn the essentials of I/O, using streams and the newer NIO APIs to read from and write to files, network sockets, and in-memory buffers.

Then we’ll tackle collections, the heart of data management in Java: lists, sets, maps, and the algorithms that let you sort, filter, and transform data with ease. You’ll see how these interfaces and implementations save you hours of custom coding.

After that, you’ll step into concurrency, learning how to create and manage threads safely, use executor services to run tasks in parallel, and coordinate work with locks, semaphores, and high-level utilities from java.util.concurrent.

Throughout the chapter, you’ll also get a taste of related libraries—date and time handling, optional values, and utilities for working with numbers and locales—showing you how the JDK’s built-in features come together to handle almost any common requirement. By the end, you’ll know which parts of the standard library to reach for whenever you need to solve a real-world problem quickly, cleanly, and efficiently.