Unfortunately there is no direct or easy way to uninstall Java, so once installed the only way to remove it and all of its components completely is to reinstall OS X; however, you can remove the Java virtual machine (the runtime) from your system and thereby perform a similar routine as an uninstall. To do this, go to the /System/Library/Frameworks/ directory and remove the file “JavaVM.framework,” which contains the Java runtimes. Additionally, empty the contents of the following directories on the system which link to the runtimes in the framework:
/System/Library/Java/JavaVirtualMachines
/Library/Java/JavaVirtualMachines