Unable to get db connection after Java 8 upgrade

I have recently upgraded an application from java 1.7 to 1.8. Rest of the libraries versions remains unchanged. I am getting the following error after the upgrade:

DEBUG 2015-11-12 09:55:12 BasicResourcePool         An exception occurred while acquiring a poolable resource. Will retry.
java.lang.NullPointerException
    at oracle.net.jndi.JndiAttrs.getAttrs(JndiAttrs.java:207)
    at oracle.net.resolver.AddrResolution.<init>(AddrResolution.java:198)
    at oracle.net.ns.NSProtocol.connect(NSProtocol.java:219)
    at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1102)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:320)
    at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:546)
    at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:236)
    at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
    at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

Hibernate configurations:

<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="hibernate.connection.url">jdbc:oracle:thin:@ldaps://XXXX,cn=OOOO,dc=WWW</property>
        <property name="hibernate.connection.username">YYYY</property>
        <property name="hibernate.statement_cache.size">0</property>
        <property name="hibernate.connection.password">ZZZZZ</property>
        <property name="hibernate.c3p0.min_size">5</property>
        <property name="hibernate.c3p0.max_size">20</property>
        <property name="hibernate.c3p0.timeout">1800</property>
        <property name="hibernate.c3p0.max_statements">0</property>
        <property name="hibernate.default_schema">YYYY</property>
        <property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
        <property name="hibernate.show_sql">true</property>
    </session-factory>
</hibernate-configuration>

Related Libraries used:

ojdbc6 11.2.0.3.0
hibernate 3.1

Problem: The dependencies contained 2 hibernate version 3.1 and 3.0 and ojdbc6 and ojdbc7. (used mvn dependency:tree -Dverbose to got dependency tree)

Solution: Excluded the other versions of hibernate and ojdbc from the dependencies.

            <dependency>
                <groupId>****</groupId>
                <artifactId>****</artifactId>
                <version>****</version>
                <exclusions>
                    <exclusion>
                        <groupId>hibernate</groupId>
                        <artifactId>hibernate</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>com.oracle</groupId>
                        <artifactId>ojdbc6</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>

As i can see from the Oracle FAQ, the jdbc driver you are using is not compatible with the Database Version and JDK8.

What are the various supported Oracle database version vs JDBC compliant versions vs JDK version supported?

I think this must be your problem. Maybe if you used ojdbc7.jar might help (not sure about this cause I haven't tested it yet - MOST PROBABLY THIS WOULD FAIL)