Step to step guide how to use 32bit version of Java in Eclipse
There is no Oracle 32 bit Java 7 for OS X. The possible OSs are listed here and OS X just has the one entry 


  Mac OS X x64  185.86 MB   jdk-7u75-macosx-x64.dmg


As Yosemite is a 64 bit OS what exactly needs to be 32 bit?