This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
This has been explained a million times in this forum. The JVM is just the program the "simulated computer" on which Java bytecode runs. A JRE includes a JVM plus all the standard Java libraries and other bits and pieces that make up a full runtime environment.
A JVM is something like a computer with a blank disk. A JRE is like a computer with an OS installed.