yes. I see in catalina.sh, if java_home is not set, it will pick up the default, my default is 1.7
Also I feel confident to say yes, because my previous default of jdk was 1.6, and when i tried to launch alfresco, it didn't launch at all, gave 404 error. Then after I upgraded jdk to 1.7, it finally was able to launch and gave me the log on page.