JDK
JDK: Java Development Kit, a software development kit for the Java language.
A toolkit that supports human input in programming languages and translates them into machine language, including JRE and JVM.
JRE
JRE: Java Runtime Environment, Java Runtime Environment.
After humans use JDK to develop programs, JRE provides a running environment for programs, and can compile programs into runnable machine language for different environments. The JRE contains the standard implementation of the JVM.
JVM
JVM: Java Virtual Machine, Java Virtual Machine.
All Java programs are compiled by the JRE into a specific language that the JVM can recognize, run on the JVM, and then the JVM interacts with different operating systems and different environments, and then under different systems.