If you are running Mac OS X 10.6 and below: Apple's Java comes pre-installed with your Mac OS and newer versions of Java should not be installed.
To install Java go to : http://java.sun.com/javase/downloads/index.jsp to download JDK 7u7
Then go to: http://www.eclipse.org/downloads/ to download Eclipse Classic 4.2, 181 MB
~ create a folder on your desktop called TEST
~ create a folder inside TEST called PROJECT1
~ run Eclipse and use the TEST folder as the workspace folder
~ add a new project called PROJECT1
~ make a new class with a simple main in it to System.out.print("Hello World");