Environment Setup

Java

Windows
Mac
Windows 32-Bit

If you want it from the source:
Java Download from Oracle

Eclipse

Most people use these options:
Windows 64-Bit
Mac 64-Bit

Only if you know you are using 32-bit use these options:
Windows 32-Bit
Mac 32-Bit

If you want it from the source:
Eclipse Download from eclipse.org

Make sure that if you get matching 64-bit or 32-bit versions of Java and Eclipse! They both have to be the same! (In general, unless something is weird with your machine (either Windows or Mac) just get the 64-bit version of each.)