The distinction is that the JDK is a package of tools for developing Java-based software, whereas the JRE is a package of tools for running Java code.

If you own an Apple device, you can't run Java—at least not as Java, although there is a project to port Java code to Objective C but that's another story. If you own a Windows-based or Android ...

Java not working for some applications: Forcing 32-bit mode <p>We recently wrote about reinstalling Java to correct problems with various applications including Mail and Safari.