Differentiate between the Java Virtual Machine, Java Development Kit, and Java Runtime Environment.
Understanding the distinction between JVM, JRE, and JDK is fundamental for any Java developer. Let's break them down. The JVM, or Java Virtual Machine, is the cornerstone of Java's platform independence. It's an abstract machine that provides a runtime environment in which Java bytecode can be executed. It interprets the compiled bytecode and translates it into native machine code for the underlying operating system. Each operating system (Windows, macOS, Linux) has a different JVM implementation, but all of them understand the same Java bytecode. Next is the JRE, or Java Runtime Environment. The JRE is the on-disk implementation of the JVM. It includes the JVM itself, plus the essential Java class libraries and other supporting files needed to *run* a Java application. If you are a user who only wants to run a Java program, you only need to install the JRE. Finally, we have the JDK, or Java Development Kit. The JDK is the complete software development kit for Java programmers. It contains everything the JRE has, plus the development tools necessary to *create* Java applications. The most important of these tools is the compiler (`javac`), which takes your `.java` source code files and compiles them into `.class` files containing bytecode. The JDK also includes a debugger, archiver, and other utilities. In short, the relationship is hierarchical: the JDK contains the JRE, and the JRE contains the JVM. As a developer, you will always install the JDK.