WebLogic always has a way to customize environment settings for domain or even for each managed servers. WebLogic 12c introduces a new option: setUserOverrides.sh. All you need to do: create a regular shell script and place it to the $DOMAIN_HOME/bin folder. WebLogic server does the rest.
The example below has helped me to fix communication issues between WebLogic IdentiyProvider and OUD.

JAVA_OPTIONS="${JAVA_OPTIONS} -Dweblogic.ssl.SSLv2HelloEnabled=false"
JAVA_OPTIONS="${JAVA_OPTIONS} -Dweblogic.security.SSL.minimumProtocolVersion=TLSv1.2"

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