Answer
This indicates a Java version mismatch between the database's own installed Java system classes and the Java version bundled with the Oracle executable being used for the install — essentially, the database and the Oracle client/home involved in the installation are out of sync on their Java versions. Resolving the underlying mismatch typically requires restoring the database to its pre-install state and raising a support case with IFS, providing the exact error message along with the database host and service details, since correcting a Java-version mismatch at this level isn't something to attempt as a self-service fix.