This seems like a "chicken before the egg" question since the JVM must be installed before your Java application can run. In order to to ensure that the JVM is installed before a user runs the application you wrote
you should use an installation tool. These kinds of tools can make sure the correct components are installed for your application. I see many Java-based programs that use Install Anywhere. There are probably others as well, but I am not familiar with them.
If a JVM is already installed, these tools can also detect if it is the correct version. Alternatively, there is probably a way to check the version once your program is running. As stated earlier, this still requires some version of the JVM to be installed already.