What are JVM, JDK, and JRE?

JVM (Java Virtual Machine) is a virtual machine that executes Java bytecode. It provides platform independence by interpreting and executing .class files.

JRE (Java Runtime Environment) is the Java runtime environment. It includes the JVM and a set of standard libraries (classes) necessary to run Java applications.

JDK (Java Development Kit) is the Java developer kit. It includes the JRE, the Java compiler (javac), debugger (jdb), and other tools necessary for developing, compiling, and debugging Java applications.

The schematic relationship: JDK includes the JRE, which includes the JVM.

+------------------+
|       JDK        |
| +----------------+ |
| |       JRE      | |
| | +--------------+ | |
| | |     JVM      | | |
| | |              | | |
| | +--------------+ | |
| |   Standard     | |
| |   Libraries    | |
| +----------------+ |
|    Development   |
|    Tools         |
+------------------+