Cocoa

Cocoa is an application environment that is what’s called object oriented. Its used to make fully Mac OS X native applications. A cocoa framework is meant to have rapid development and be very productive. It takes 100% full advantage of every single underlying technology through out the OS.

Carbon

Carbon includes a set of what’s called APIs (Application Program Interfaces) that are used to create OS X applications using C+ and C++ that can take advantage of Quartz 2D graphics, multi-processing, and other OS X underlying technologies. It provides services such as OpenGL, drawing, the Mach microkernel and BSD Unix services. Carbon apps don’t really look any different from the users eye from a cocoa app. It’s really how the application was programmed. Carbon apps can do fairly similar things as cocoa apps, it generally just takes more code to do the same thing. The difference is how the apps are programmed to get something accomplished.

Java

Java is built into the Mac OS using the Java 2 foundation. It allows java developers to easily distribute their java apps as native OS X applications to users. Developers can also take advantage of the Mac OS Java specific features as well as some cocoa based API’s.