java.sql.SQLException
Listener refused the connection with the following error:
ORA-12516, TNS:listener could not find available handler with matching protocol stack

        at oracle.jdbc.driver.T4CConnection.logon (T4CConnection.java:412)
        at oracle.jdbc.driver.PhysicalConnection.<init> (PhysicalConnection.java:531)
        at oracle.jdbc.driver.T4CConnection.<init> (T4CConnection.java:221)

jdbc:oracle:thin:@mydb-scan:1521/TESTDBRAC