What must I do in the case of java sql sqlrecoverableexception?

 During installation of an application, got following error for Oracle database -

Closed Connection java.sql.SQLRecoverableException: Closed Connection at

oracle.jdbc.driver.PhysicalConnection.prepareStatementInternal(PhysicalConnection.java:4079) ~

[ojdbc7.jar:12.1.0.1.0] at 

oracle.jdbc.driver.PhysicalConnection.prepareStatement(PhysicalConnection.java:4045) ~

[ojdbc7.jar:12.1.0.1.0] at 

oracle.jdbc.driver.PhysicalConnection.prepareStatement(PhysicalConnection.java:3951) ~

[ojdbc7.jar:12.1.0.1.0] 

An internet search suggested this could be a firewall but the firewall is disabled on the machine where it is run.

Could you please help to understand what could be wrong here?

Oracle version is - 12.1.0