The Java Development Kit (JDK) is a software development environment used for developing Java applications. It includes essential tools such as the Java compiler, which converts Java code into bytecode, and the Java Runtime Environment (JRE), which allows the execution of Java programs. The JDK also provides libraries and documentation to help developers write and debug their code. Developers use the JDK to create a wide range of applications, from mobile apps to large-scale enterprise systems. It is an essential component for anyone looking to work with the Java programming language and is available for various operating systems, including Windows, macOS, and Linux.