Install Java JRE 6 (next to JRE 7) on OS X 10.10 Yosemite?
JavaForOSX2014-001.dmg contains Java for Mac OS X (1.6.0_65-b14-462). It will be installed to /System/Library/Java and /System/Library/Frameworks while Oracle Java is located at /Library/Java. No file will be overwritten.
To avoid any trouble (especially with your $JAVA_HOME/$PATH) consider setting up a Mac OS X VM in VMWare, Parallels or VirtualBox with JRE6 only.