JNDI - Java Naming and Directory Interface

Key Characteristics

• • Standard Java API: Part of the Java SE and Java EE platforms, providing a consistent way to interact with naming and directory services.
  • Service Provider Interface (SPI): JNDI includes an SPI that allows different naming and directory service implementations (e.g., LDAP, DNS, RMI, COS Naming, file systems) to be plugged in.
  • Resource Abstraction: Decouples application code from the physical location and configuration details of resources, allowing resources to be managed centrally.
  • Logical Naming: Resources are accessed using logical names (e.g., java:comp/env/jdbc/DB2DS), which promotes portability and simplifies configuration changes.
  • Hierarchical Structure: Naming services often present resources in a hierarchical tree structure, similar to a file system, allowing for organized lookups.
  • Mainframe Relevance: Crucial for Java applications on z/OS to interact with traditional mainframe resources and services, often facilitated by application servers like WebSphere for z/OS.

Use Cases

• • DB2 Data Source Lookup: A Java application running on z/OS (e.g., a batch job or a servlet in WebSphere for z/OS) uses JNDI to look up a pre-configured javax.sql.DataSource object to connect to a DB2 for z/OS subsystem.
  • IBM MQ Connection Factory: A Java Message Service (JMS) application on z/OS retrieves an MQConnectionFactory object via JNDI to establish connections to an IBM MQ for z/OS queue manager.
  • CICS EJB Access: A Java EE application deployed in WebSphere for z/OS uses JNDI to locate the home interface of an Enterprise JavaBean (EJB) deployed within CICS Transaction Server for z/OS.
  • Enterprise Bean (EJB) Lookup: Java EE applications running on WebSphere for z/OS use JNDI to find and invoke other EJBs deployed within the same or different application servers.
  • External Directory Integration: A Java application on z/OS might use JNDI to connect to an LDAP directory (e.g., IBM Security Directory Server for z/OS) for user authentication, authorization, or retrieving configuration parameters.

Related Concepts