Data sources are created with OCI enabled. For this, Oracle Instant Client is required, below steps needs to be followed

• Download Oracle Instant Client corresponding to the used Oracle DB and java (x64 or x32):

  https://www.oracle.com/database/technologies/instant-client/downloads.html

• Set {ORACLE_HOME} in the environment variable.
• Update the environment variable LD_LIBRARY_PATH as {ORACLE_HOME}/lib. This is to load all the .so files.
• Ensure that the ojdbc*.jar file in {WL_HOME}/server/lib/ojdbc*.jar is the same as the file {ORACLE_HOME}/jdbc/lib/ojdbc*.jar. This is to ensure compatibility.
• Update LD_LIBRARY_PATH in StartWebLogic.sh or in setDomainEnv.sh. This must be the path of directory where Oracle Instant Client is installed.
• If you are still not able to load the .so files, then you need to update the EXTRA_JAVA_PROPERTIES by setting Djava.library.path as {ORACLE_HOME}/lib in StartWebLogic.sh or in setDomainEnv.sh.