What is JNDI What is its basic use When is it used

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What is JNDI  What is its basic use  When is it used

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What is JNDI    JNDI stands for Java Naming and Directory Interface  It comes standard with J2EE    What is its basic use   With this API  you can access many types of data  like objects  devices  files of naming and directory services  eg  it is used by EJB to find remote objects  JNDI is designed to provide a common interface to access existing services like DNS  NDS  LDAP  CORBA and RMI    When it is used   You can use the JNDI to perform naming operations  including read operations and operations for updating the namespace  The following operations are described here

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What is JNDI     It stands for Java Naming and Directory Interface      What is its basic use    JNDI allows distributed applications to look up services in an abstract  resource-independent way       When it is used    The most common use case is to set up a database connection pool on a Java EE application server  Any application that s deployed on that server can gain access to the connections they need using the JNDI name java comp env FooBarPool without having to know the details about the connection   This has several advantages     If you have a deployment sequence where apps move from devl- gt int- gt test- gt prod environments  you can use the same JNDI name in each environment and hide the actual database being used  Applications don t have to change as they migrate between environments  You can minimize the number of folks who need to know the credentials for accessing a production database  Only the Java EE app server needs to know if you use JNDI

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JNDI in layman s terms is basically an Interface for being able to get instances of internal External resources such as    javax sql DataSource     javax jms Connection-Factory    javax jms QueueConnectionFactory    javax jms TopicConnectionFactory    javax mail Session  java net URL    javax resource cci ConnectionFactory    or any other type defined by a JCA resource adapter  It provides a syntax in being able to create access whether they are internal or external  i e  comp env in this instance means where component environment  there are lots of other syntax    jndiContext lookup  java comp env persistence customerDB

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I will use one example to explain how JNDI can be used to configure database without any application developer knowing username and password of the database   1  We have configured the data source in JBoss server s standalone-full xml  Additionally  we can configure pool details also     lt datasource jta  false  jndi-name  java  DEV DS  pool-name  DEV  enabled  true  use-ccm  false  gt                   lt connection-url gt jdbc oracle thin   lt IP gt  1521 DEV lt  connection-url gt                   lt driver-class gt oracle jdbc OracleDriver lt  driver-class gt                   lt driver gt oracle lt  driver gt                   lt security gt                       lt user-name gt usname lt  user-name gt                       lt password gt pass lt  password gt                       lt  security gt                       lt security gt     lt security-domain gt encryptedSecurityDomain lt  security-domain gt                       lt  security gt                    lt validation gt                       lt validate-on-match gt false lt  validate-on-match gt                       lt background-validation gt false lt  background-validation gt                       lt background-validation-millis gt 1 lt  background-validation-millis gt                   lt  validation gt                   lt statement gt                       lt prepared-statement-cache-size gt 0 lt  prepared-statement-cache-size gt                       lt share-prepared-statements gt false lt  share-prepared-statements gt                       lt pool gt                           lt min-pool-size gt 5 lt  min-pool-size gt                           lt max-pool-size gt 10 lt  max-pool-size gt                       lt  pool gt                   lt  statement gt               lt  datasource gt      Now  this jndi-name and its associated datasource object  will be available for our application application   2  We can retrieve this datasource object using JndiDataSourceLookup class     Spring will instantiate the datasource bean  after we provide the jndi-name   Now  we can change the pool size  user name or password as per our environment or requirement  but it will not impact the application   Note   encryptedSecurityDomain  we need to configure it separately in JBoss server like    lt security-domain name  encryptedSecurityDomain  cache-type  default  gt                       lt authentication gt                           lt login-module code  org picketbox datasource security SecureIdentityLoginModule  flag  required  gt                               lt module-option name  username  value   lt usernamefordb gt    gt                               lt module-option name  password  value  894c8a6aegc8d028ce169c596d67afd0   gt                           lt  login-module gt                       lt  authentication gt                   lt  security-domain gt    This is one of the use cases  Hope it clarifies

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A naming service associates names with objects and finds objects based on their given names  RMI registry is a good example of a naming service   JNDI provides a common interface to many existing naming services  such as LDAP  DNS   Without JNDI  the location or access information of remote resources would have to be hard-coded in applications or made available in a configuration  Maintaining this information is quite tedious and error prone

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The best explanation to me is given here  What is JNDI     It is an API to providing access to a directory service  that is  a service mapping name  strings  with objects  reference to remote objects or simple data  This is called   binding  The set of bindings is called the context  Applications use the JNDI interface to access resources       To put it very simply  it is like a hashmap with a String key and Object values representing resources on the web     What Issues Does JNDI Solve     Without JNDI  the location or access information of remote resources would have to be hard-coded in applications or made available in a configuration  Maintaining this information is quite tedious and error prone       If a resources has been relocated on another server  with another IP address  for example  all applications using this resource would have to be updated with this new information  With JNDI  this is not necessary  Only the corresponding resource binding has to be updated  Applications can still access it with its name and the relocation is transparent

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What is JNDI     The Java Naming and Directory InterfaceTM  JNDI  is an application programming interface  API  that provides naming and directory functionality to applications written using the JavaTM programming language  It is defined to be independent of any specific directory service implementation  Thus a variety of directories new  emerging  and already deployed  can be accessed in a common way       What is its basic use    Most of it is covered in the above answer but I would like to provide architecture here so that above will make more sense     To use the JNDI  you must have the JNDI classes and one or more service providers  The Java 2 SDK  v1 3 includes three service providers for the following naming directory services     Lightweight Directory Access Protocol  LDAP   Common Object Request Broker Architecture  CORBA  Common Object Services  COS  name service  Java Remote Method Invocation  RMI  Registry    So basically you create objects and register them on the directory services which you can later do lookup and execute operation on

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JNDI Overview     JNDI is an API specified in Java   technology that provides naming and   directory functionality to   applications written in the Java   programming language  It is designed   especially for the Java platform using   Java s object model  Using JNDI    applications based on Java technology   can store and retrieve named Java   objects of any type  In addition  JNDI   provides methods for performing   standard directory operations  such as   associating attributes with objects   and searching for objects using their   attributes       JNDI is also defined independent of   any specific naming or directory   service implementation  It enables   applications to access different    possibly multiple  naming and   directory services using a common API    Different naming and directory service   providers can be plugged in seamlessly   behind this common API  This enables   Java technology-based applications to   take advantage of information in a   variety of existing naming and   directory services  such as LDAP  NDS    DNS  and NIS YP   as well as enabling   the applications to coexist with   legacy software and systems       Using JNDI as a tool  you can build   new powerful and portable applications   that not only take advantage of Java s   object model but are also   well-integrated with the environment   in which they are deployed    Reference

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I am just curious why the official docs are so ignored which elaborate the details meticulously already    But if you d like to understand the cases  please refer to duffymo s answer      The Java Naming and Directory InterfaceTM  JNDI  is an application programming interface  API  that provides naming and directory functionality to applications written using the JavaTM programming language  It is defined to be independent of any specific directory service implementation  Thus a variety of directories--new  emerging  and already deployed--can be accessed in a common way    And its architecture    And normally how you use it

[jndi] What is JNDI? What is its basic use? When is it used?

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