Use following SQL to find out the ISOLATION LEVEL used by DB2 packages.
SELECT 'SHOW_RSETS' "STORED PROCEDURE", SUBSTR(PKGNAME,1,18) PACKAGE, "ISOLATION" FROM syscat.packages WHERE pkgname = (SELECT deps.bname PACKAGE FROM sysibm.sysdependencies deps, sysibm.sysroutines procs WHERE deps.dtype = 'F' AND deps.btype = 'K' AND procs.specificname = deps.dname AND procs.routineschema = deps.dschema AND procs.routinename = 'Stored_Procedure_name') @