JAVA_HOME property hidden in the WebLogic binaries and used in domain creation

When installing WebLogic, a JDK is picked up, and stored in several "hidden" files:

$WEBLOGIC_HOME/coherence_3.6/.product.properties (JAVAHOME and JAVA_HOME)

$WEBLOGIC_HOME/oracle_common/inventory/Components21/oracle.swd.oui/11.1.0.9.0/context.xml

$WEBLOGIC_HOME/osb/inventory/Components21/oracle.swd.oui/11.1.0.9.0/context.xml

$WEBLOGIC_HOME/wlserver_10.3/.product.properties (JAVA_HOME, WLS_JAVA_HOME, JAVAHOME)

and possibly others
One of these values is stored in the $DOMAIN_HOME/bin/setDomainEnv.sh
If by any chance you change JDK (NOT RECOMMENDED AT ALL!!!), I would recommend to reinstall the binaries altogether.