Hello,
for supported OS X versions with SAP GU for Java 7.30, please refer to Note 1758540 - SAP GUI for Java: Requirements for Release 7.30.
SAP GUI for Java 7.20 is no longer supported.
Oracle does not support Java 7 on OS X 10.6, therefore Java 6 update 15 is the latest one. Latter however is not qualified to run SAP GUI for Java 7.30.
Best regards
Rolf-Martin