We have just released the 2.3.5 version of the UnboundID LDAP SDK for Java. You can get the latest release online at the UnboundID website or the SourceForge project page, and it’s also available in the Maven Central Repository.

There are a lot of improvements in this release over the 2.3.4 version. A full copy of the release notes for this version may be found on the UnboundID website, but many of the improvements are related to connection pooling, load balancing, and failover, but there are other additions and a number of bug fixes also included in this release. Some of the most notable changes include:

• Added a new fewest connections server set. If used to create a connection pool in which connections span multiple servers, the pool will try to send each newly-created connection to the server with the fewest number of active connections already open by that server set.
• Updated the LDAPConnectionPool class to make it possible to specify an alternate maximum connection age that should be used for connections created to replace a defunct connection. In the event that a directory server goes down and pooled connections are shifted to other servers, this can help connections fail back more quickly.
• Updated the failover server set to make it possible to specify an alternate maximum connection age for pooled connections that are established to a server other than the most-preferred server. This can help ensure that failover connections are able to fail back more quickly when the most-preferred server becomes available again.
• Added a new version of the LDAPConnectionPool.getConnection method that can be used to request a connection to a specific server (based on address and port), if such a connection is readily available.
• Added a new LDAPConnectionPool.discardConnection method that can be used to close a connection that had been checked out from the pool without creating a new connection in its place. This can be used to reduce the size of the pool if desired.
• Added a new LDAPConnection.getLastCommunicationTime method that can be used to determine the time that the connection was last used to send a request to or read a response from the directory server, and by extension, the length of time that connection has been idle.
• Updated the connection pool so that by default, connections which have reached their maximum age will only be closed and replaced by the background health check thread. Previously, the LDAP SDK would also check the connection age when a connection was released back to the pool (and this option is still available if desired), which could cause excess load against the directory server as a result of a number of connections being closed and re-established concurrently. Further, checking the maximum connection age at the time the connection is released back to the pool could have an adverse impact on the perceived response time for an operation because in some cases the LDAP SDK could close and re-establish the connection before the result of the previous operation was made available to the caller.
• Updated the LDIF writer to add the ability to write the version header at the top of an LDIF file, to ensure that modify change records include a trailing dash after the last change in accordance with the LDIF specification, and to fix a bug that could cause it to behave incorrectly when configured with an LDIF writer entry translator that created a new entry as opposed to updating the entry that was provided to it.
• Dramatically improved examples included in the Javadoc documentation. All of these examples now have unit test coverage to ensure that the code is valid, and many of the examples now reflect a more real-world usage.
• Improved the quality of error messages that may be returned for operations that fail as a result of a client-side timeout, or for certain kinds of SASL authentication failures. Also improved the ability to perform low-level debugging for responses received on connections operating in synchronous mode.
• Updated the in-memory directory server to support enforcing a maximum size limit for searches.
• Added a couple of example tools that can be used to find supposedly-unique attribute values which appear in multiple entries, or to find entries with DN references to other entries that don’t exist.
• Made a number of improvements around the ability to establish SSL-based connections, or to secure existing insecure connections via StartTLS. Improvements include making it possible to specify the default SSL protocol via a system property so that no code change may be required to set a different default protocol, allowing the ability to define a timeout for StartTLS processing as part of the process for establishing a StartTLS-protected connection.
• Fixed a bug that could cause the LDAP SDK to enter an infinite loop when attempting to read data from a malformed intermediate response.
• Fixed a bug that could cause problems in handling the string representation of a search filter that contained non-UTF-8 data.