My Oracle Support Banner

JDBC Connections Fail with ORA-12520 (Doc ID 2660207.1)

Last updated on APRIL 21, 2020

Applies to:

JDBC - Version 10.2.0.5 and later
Information in this document applies to any platform.

Symptoms

Application using JDBC 11.2.0.3 reports the following exception during connection to a 12.1.0.2 database :

oracle.net.ns.NetException: Listener refused the connection with the following error:
ORA-12520, TNS:listener could not find available handler for requested type of server
  at oracle.net.ns.NSProtocolStream.negotiateConnection(NSProtocolStream.java:275)
  at oracle.net.ns.NSProtocol.connect(NSProtocol.java:264)
  at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1452)
  at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:496)
  at oracle.jdbc.driver.PhysicalConnection.connect(PhysicalConnection.java:662)
  at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
  at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:560)
  at java.sql.DriverManager.getConnection(DriverManager.java:664)

Cause

To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!


In this Document
Symptoms
Cause
Solution
References


My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.