JDK (Java Development Kit): A JDK is an implementation of the Java SE platform that is used to develop Java applications. The JDK includes the JRE as well as tools for developing, debugging, and monitoring Java applications. For example, the JDK includes the javac compiler, which is used to compile Java source code into Java bytecode.
JRE (Java Runtime Environment): A JRE is an implementation of the Java SE platform that is used to run Java applications. The JRE includes the Java Virtual Machine (JVM), class libraries, and other components necessary for running a Java application. For example, the JRE includes the java command, which is used to launch Java applications.
JVM (Java Virtual Machine): A JVM is a virtual machine that runs Java bytecode. The JVM is responsible for interpreting and executing Java bytecode. It also provides runtime services such as memory management, threading, and garbage collection.