what is jvm jdk and jre

1Java Virtual Machine: JVM is an abstract machine. 
2It actually runs by Java code. Most people know Java with this slogan 
3"Write once and run everywhere' This slogan is because of JVM. 
4• Java Runtime Environment : JRE is what we need to run a Java program 
5and containsset of libraries and other files that JVM uses at run time. 
6JRE = JVM + Library Classes 
7• Java Development Kit : JDK is what we need to compile Java source code 
8and contains JRE, development tools. JDK = JRE + Development tools

1JVM:
21.	JVM is an abstract machine. 
3    Because it doesn't physically exist.
42.	It is a very important part of both JDK
5     and JRE because it is inbuilt in both. 
63.	Whatever Java program we want to run, goes into JVM. 
74.	And JVM is responsible for loading,
8    verifying and executing the java program 
9    line by line hence it is also known as interpreter.
10    
11The Java Development Kit (JDK) is a software development 
12environment used for developing Java applications. 
13It includes:
14	Java Virtual Machine, 
15	Java Runtime Environment,
16	Loader, 
17	Java compiler, 
18	Documentation generator 
19	Archiver (jar), 
20	Other tools needed in Java development.
21    
22 Java Runtime Environment :
23	It physically exists. 
24	The Java Runtime Environment provides
25    the minimum requirements such as libraries
26    and Class Loader for executing a 
27    Java application on JVM. 
28	It consists of the Java Virtual Machine
29    core classes, and supporting files.    

1JDK is a software development kit whereas JRE is a software bundle that allows
2Java program to run, whereas JVM is an environment for executing bytecode.
3The full form of JDK is Java Development Kit, while the full form of JRE is Java
4Runtime Environment, while the full form of JVM is Java Virtual Machine.