How to identify mac os Eclipse is 32 bit or 64 bit ?

These are the flags you can look at to identify whether your Mac Eclipse is 32 bit or 64 bit ?

Navigate to this menu:
Eclipse ->About Eclipse -> Click on "Installation Details" -> Click on "Configuration" tab->

And look for these parameters:

macosx
-ws
cocoa
-arch
x86_64

Here x86_64 represents 64 bit eclipse.

For 32 bit eclipse, you will find only x86. 

macosx
-ws
cocoa
-arch
x86


There are few more parameters that also represent the same.
org.osgi.framework.processor=x86-64
osgi.arch=x86_64