I’ve been working with LDAP directory servers for about ten years, and for that entire time I’ve also been writing code.  I’ve written a lot of server-side code in the course of building directory servers, but I’ve written even more client-side code for interacting with them.  Unfortunately, I’ve always been a bit disappointed with the APIs that are available for LDAP communication, especially those for use in Java applications.

Java should be a great language for writing directory-enabled applications.  It’s fast, has a broad standard library, offers a number of frameworks for developing web-based and desktop applications, and it’s easy to write robust code in a short period of time.  Unfortunately, the APIs available for LDAP communication are pretty limited.  JNDI is a common choice because it’s part of the core Java runtime, but it’s very cumbersome and confusing and provides rather limited access to the elements of the LDAP protocol.  The Netscape Directory SDK for Java is more user friendly than JNDI, but it’s fairly buggy (especially under load), supports a pretty limited set of controls and extended operations, and is really showing its age after not having any new releases since 2002.  I’ve never actually used JLDAP, but it looks to expose pretty much the same API as the Netscape SDK and has also gone several years without a new release.

Today, UnboundID is correcting this problem with our release of the UnboundID LDAP SDK for Java.  It is a user-friendly, high-performance, feature-rich, and completely free Java API for communicating with LDAP directory servers and performing other directory-related tasks.  Some of the benefits that it provides include:

• It is completely free to use and redistribute.  The LDAP SDK is available under either the GNU General Public License v2 (GPLv2) or the UnboundID LDAP SDK Free Use License.
• It provides a broad feature set.  In addition to providing full support for the core LDAPv3 protocol, it also includes support for 17 standard controls, 4 standard extended operations, and 6 standard SASL mechanisms.  It also provides a number of related APIs for things like LDIF, base64 and ASN.1 parsing, working with root DSE and changelog entries, enhanced schema support, command line argument processing, and SSL/TLS communication.
• It is much more convenient and easy to use than other LDAP APIs,  It is often possible to do what you want with quite a bit less code than the alternatives, and its use of Java features like generics, enums, annotations, and varargs can further enhance the development experience.
• It provides support for connection pooling and client-side failover and load balancing.  Connections can be easily spread across multiple directory servers, and you can even have read and write operations sent to different sets of servers.  The connection pool classes implement the same interface as individual connections, so you can process operations using pooled connections without needing to deal with checking out and releasing connections and performing all of the necessary error handling (although that’s possible too if you need it).
• It provides excellent performance and scalability.  My testing has shown it to be significantly faster than either JNDI or the Netscape SDK, and the searchrate tool that we include as an example can handily outperform the popular C-based version provided by another vendor.
• It has no external dependencies.  Everything is included in a single jar file, and the only requirement is a Java SE 5.0 or higher runtime.
• It is robust and reliable.  We have an extensive test suite for the SDK itself with over 26,000 test cases covering over 94% of the code.  The LDAP SDK is also used as an integral part of other UnboundID products, so it benefits from the testing we do for them as well.  It’s frequently subjected to very heavy and highly concurrent workloads so there shouldn’t be any surprises when moving your applications from testing into production (at least, not because of the LDAP SDK).
• It includes generous documentation.  In addition to a more thorough overview of the benefits our LDAP SDK provides over other the alternatives, it also includes a getting started guide, Javadoc documentation with lots of examples, and a number of sample programs demonstrating the use of various SDK components.
• Commercial support is available.  This can help ensure fast access to patches for any problems found in the LDAP SDK, and may also be used to request enhancements and additional functionality.  Developer support is also available to assist you in using the LDAP SDK to create directory-enabled applications.

You can find the UnboundID LDAP SDK for Java available for download at http://www.unboundid.com/products/ldapsdk/.  All of the documentation is available there as well (and also in the product download), including some frequently asked questions and a more detailed list of the advantages it offers over other LDAP APIs.