what is jdk and jvm code example

Example 1: JDK JRE JVM

Java Virtual Machine: JVM is an abstract machine. 
It actually runs by Java code. Most people know Java with this slogan 
"Write once and run everywhere' This slogan is because of JVM. 
• Java Runtime Environment : JRE is what we need to run a Java program 
and containsset of libraries and other files that JVM uses at run time. 
JRE = JVM + Library Classes 
• Java Development Kit : JDK is what we need to compile Java source code 
and contains JRE, development tools. JDK = JRE + Development tools

Example 2: Explain JDK, JRE and JVM?

JDK is a software development kit whereas JRE is a software bundle that allows
Java program to run, whereas JVM is an environment for executing bytecode.
The full form of JDK is Java Development Kit, while the full form of JRE is Java
Runtime Environment, while the full form of JVM is Java Virtual Machine.