What does java comp env do

Question

I just spent too much time of my day trying to figure out some errors when hooking up some JNDI factory bean. The problem turned out to be that instead of this...

<bean id="someId" class="org.springframework.jndi.JndiObjectFactoryBean">
  <property name="jndiName" value="java:comp/env/jdbc/loc"/>
</bean>

I had actually written this...

<bean id="someId" class="org.springframework.jndi.JndiObjectFactoryBean">
  <property name="jndiName" value="jdbc/loc"/>
</bean>

I infer that the java:comp/env/ perhaps references some environment variable and makes it so that, ultimately, my context file is looked at. The only difference is java:comp/env/. From an expert's mouth, what does that do?

Without the java:comp/env/ prefix in the value, I would get an error that said "Name jdbc is not bound in this Context".

User · Answer

There is also a property resourceRef of JndiObjectFactoryBean that is  when set to true  used to automatically prepend the string java comp env  if it is not already present    lt bean id  someId  class  org springframework jndi JndiObjectFactoryBean  gt     lt property name  jndiName  value  jdbc loc   gt     lt property name  resourceRef  value  true   gt   lt  bean gt

User · Answer

After several attempts and going deep in Tomcat s source code I found out that the simple property useNaming  false  did the trick   Now Tomcat resolves names java  liferay instead of java comp env liferay

User · Answer

Quoting https   web archive org web 20140227201242 http   v1 dione zcu cz java docs jndi-1 2 tutorial beyond misc policy html     At the root context of the namespace   is a binding with the name  comp     which is bound to a subtree reserved   for component-related bindings  The   name  comp  is short for component    There are no other bindings at the   root context  However  the root   context is reserved for the future   expansion of the policy  specifically   for naming resources that are tied not   to the component itself but to other   types of entities such as users or   departments  For example  future   policies might allow you to name users   and organizations departments by using   names such as  java user alice  and    java org engineering        In the  comp  context  there are two   bindings   env  and  UserTransaction     The name  env  is bound to a subtree   that is reserved for the component s   environment-related bindings  as   defined by its deployment descriptor     env  is short for environment  The   J2EE recommends  but does not require    the following structure for the  env    namespace    So the binding you did from spring or  for example  from a tomcat context descriptor go by default under java comp env   For example  if your configuration is    lt bean id  someId  class  org springframework jndi JndiObjectFactoryBean  gt     lt property name  jndiName  value  foo   gt   lt  bean gt    Then you can access it directly using   Context ctx   new InitialContext    DataSource ds    DataSource ctx lookup  java comp env foo      or you could make an intermediate step so you don t have to specify  java comp env  for every resource you retrieve   Context ctx   new InitialContext    Context envCtx    Context ctx lookup  java comp env    DataSource ds    DataSource envCtx lookup  foo

[spring] What does java:comp/env/ do?

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