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JNDI Lookup with Resource annotation always NULL

I've got a WebApp with Tomcat 10, Java11 using Jersey3.
I defined a ConnectionPool in my context.xml for handling the connection to my OracleDB and now I'm trying to access the DataSource within my controller through a #Resource annotation. This should invoke a JNDI-lookup. Unfortunately, I always get a NPE as it seems not to find the resource while running... What am I doing wrong? Or what would the correct mappedName / lookup be?
#Path("/data")
public class DataController {
#Context
ServletContext context;
#Resource(lookup = "java:/jdbc/myDB") //also tried java:/comp/env/jdbc/myDB and mappedName="jdbc/myDB"
protected DataSource ds; //always null
<Context name="myapp">
<Resource type="javax.sql.DataSource"
name="jdbc/myDB"
factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
driverClassName="oracle.jdbc.OracleDriver"
url="jdbc:oracle:thin:#//localhost:1521/orcl"
username="xy"
password="xy"/>
According to the tutorials, a ref-link is optional when I define the resource directly in the context.xml.
Thanks for any input!

This link is about jboss, but would seem relevant to you too. It says that according to the specification, Resource annotation to do JNDI lookups would only work with EJBs, so it wouldn't work for your case.
A workaround is to do the programmatic way to see if your datasource is working:
Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
DataSource bean = (DataSource ) envCtx.lookup("jdbc/myDB");
If you can find your datasource you can then try to optimize to avoid "manual" lookup above.

simple string value by JNDI in Java

How can i set simple string value in configuration of tomcat and then read in java application?
context.xml
<ResourceLink name="global/test" global="testing" type="java.lang.String" />
server.xml
<Enviroment name="testing" value="myUser" type="java.lang.String"/>
web.xml in application
<resource-env-ref>
<resource-env-ref-name>global/test</resource-env-ref-name>
<resource-env-ref-type>java.lang.String</resource-env-ref-type>
</resource-env-ref>
in my java application
public String getValue(){
return new JndiDataSourceLookup().getDataSource("global/test").toString();
}
When i Run tomcat, i see these errors...
org.springframework.jdbc.datasource.lookup.DataSourceLookupFailureException: Failed to look up JNDI DataSource with name 'global/test'; nested exception is javax.naming.NameNotFoundException: Name [global/test] is not bound in this Context. Unable to find [global].
javax.naming.NameNotFoundException: Name [global/test] is not bound in this Context. Unable to find [global].

In your web.xml use,
<env-entry>
<description>Sample env entry</description>
<env-entry-name>isConnected</env-entry-name>
<env-entry-type>java.lang.Boolean</env-entry-type><!--order matters -->
<env-entry-value>true</env-entry-value>
</env-entry>
In code,
try {
Context initCxt = new InitialContext();
Boolean isConn = (Boolean)initCxt.lookup("java:comp/env/isConnected");
System.out.println(isConn.toString());
// one could use relative names into the sub-context
Context envContext = (Context) initCxt.lookup("java:comp/env");
Boolean isConn2 = (Boolean)envContext.lookup("isConnected");
System.out.println(isConn2.toString());
} catch (NamingException e) {
e.printStackTrace();
}
Have a look here Naming service tutorial to get a good understanding of InitialContext and JNDI.

I don't know what's inside JndiDataSourceLookup().getDataSource("global/test") but by the name of it, it should return a DataSoruce not a string.
If your lookup is local, simply do
Context ctx = new InitialContext();
String s = (String) ctx.lookup("global/test");
or if you are in a javaee container,
#Resource(name="global/test")
String testString;
and finally in your ejb-jar.xml
<env-entry>
<description>The name was explicitly set in the annotation so the classname prefix isn't required</description>
<env-entry-name>global/test</env-entry-name>
<env-entry-type>java.lang.String</env-entry-type>
<env-entry-value>StringValue</env-entry-value>
</env-entry>
Refer this link: http://tomee.apache.org/examples-trunk/injection-of-env-entry/README.html
Your configuration of context.xml, server.xml, and web.xml aren't gonna work.

Glassfish jdbc/database lookup failed

I hope I am not asking a duplicate question just because I was unable to find an answer.
I am getting this error:
javax.naming.NamingException: Lookup failed for 'jdbc/osclassDB' in SerialContext
This is what I did: I set up a JDBC Connection Pool and a JDBC Resource pointing to that pool (both in Glassfish).
Then I told my web.xml that there is a JDBC Resource:
<resource-ref>
<res-ref-name>jdbc/osclassDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
<res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>
And then I tried using that resource in a Servlet:
Connection connection = null;
try {
InitialContext initialContext = new InitialContext();
//Context dbContext = (Context) initialContext.lookup("java:comp/env");
DataSource dataSource = (DataSource) initialContext.lookup("jdbc/osclassDB");
connection = dataSource.getConnection();
if (connection == null) {
throw new SQLException("Error establishing connection!");
}
// some queries here
}
// catch and finally close connection
But when I call the Servlet it throws me the NamingException and tells me that the Lookup failed for 'jdbc/osclassDB' in SerialContext
What am I doing wrong here? is it the web.xml? did I miss something?
Thank you for your help!

Solved the problem:
1st by adding a sun-web.xml that links the resource reference from the web.xml to an actual jndi-name (the one I setup on Glassfish). Normally, that shouldn't be necessary (says Oracle) but I did it anyways [Edit: as it turns out, it is really not necessary! ]
2nd I left out the "jdbc". In the servlet, the web.xml and the sun-web.xml it is now just called "osclassDB" (my resource name) instead of "jdbc/osclassDB"
now it looks like this:
web.xml
<resource-ref>
<res-ref-name>osclassDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
<res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>
sun-web.xml
<resource-ref>
<res-ref-name>osclassDB</res-ref-name>
<jndi-name>osclassDB</jndi-name>
</resource-ref>
in the servlet
Context dbContext = (Context) initialContext.lookup("java:comp/env");
DataSource dataSource = (DataSource) dbContext.lookup("osclassDB");
connection = dataSource.getConnection();
[Edit:] the sun-web.xml is really not necessary

How to store string values in context.xml

I'd like to store connection URLs in a JNDI binding for my Tomcat application. Since Tomcat uses context.xml for JNDI resource defining, I need to figure out the propert way to store a String (or multiple strings for multiple connections) in context.xml.
My reason for doing this is so that I can define different strings for different environments, and load them through JNDI.
Usually, I see entries like so:
<Context ...>
<Resource name="someName" auth="Container"
type="someFullyQualifiedClassName"
description="Some description."/>
</Context>
Is it really just as simple as:
<Context ...>
<Resource name="myConnectionURL" auth="Container"
type="java.lang.String"
description="A connection URL string."/>
</Context>
If so, where do I actually store the String value?!?! And if it's not correct, then what is the proper way for me to store, for instance, "amqp:5272//blah.example.com&param1=4" in context.xml so I could then look it up like so:
Context ctx = new InitialContext();
String connectionURL = (String)ctx.lookup("myConnectionURL");
Thanks in advance!

You can use an Environmenttag:
<Context>
<Environment name="myConnectionURL" value="amqp:5272//blah.example.com&param1=4" type="java.lang.String"/>
</Context>
And you can read it almost as you specified in the question:
InitialContext initialContext = new InitialContext();
Context environmentContext = (Context) initialContext.lookup("java:/comp/env");
String connectionURL = (String) environmentContext.lookup("myConnectionURL");
This is much the same as using a Parameter tag, but without the need for a ServletContext.

You can configure named values that will be made visible to the web application as servlet context initialization parameters by nesting elements inside this element. For example, you can create an initialization parameter like this:
<Context>
...
<Parameter name="companyName" value="My Company, Incorporated"
override="false"/>
...
</Context>
This is equivalent to the inclusion of the following element in the web application deployment descriptor (/WEB-INF/web.xml):
<context-param>
<param-name>companyName</param-name>
<param-value>My Company, Incorporated</param-value>
</context-param>
Your java code looks like this
ServletContext sc = getServletContext();
String companyName = sc.getInitParameter("companyName");
Please see the reference http://tomcat.apache.org/tomcat-7.0-doc/config/context.html

JNDI path Tomcat vs. Jboss

I have DataSource which is configured on Tomcat 6 in context.xml as MyDataSource.
And I'm fetching it the following way:
DataSource dataSource;
try {
dataSource = (DataSource) new InitialContext().lookup("java:comp/env/MyDataSource");
} catch (NamingException e) {
throw new DaoConfigurationException(
"DataSource '" + url + "' is missing in JNDI.", e);
}
Everything works fine. Now I'm exporting this code to Jboss AP 6. and I configured my dataSource and its connection pool as local-tx dataSource under the same name.
When I'm executing the code above, I'm getting NamingException exception. after some investigation I've found that correct way to call my DataSource under Jboss is
dataSource = (DataSource) new InitialContext().lookup("java:/MyDataSource");
Can anybody explain me why should I omit "comp/env" in my JNDI path under Jboss?

The portable approach for defining data sources is to use a resource reference. Resource references enable you to define the JNDI name for your data source, relative to your application naming context (java:comp/env), and then map that logical reference to the physical resource defined in the application server, whose JNDI name is proprietary to the application server vendor. This approach enables your code and assembly to be portable to any compliant application server.
Step 1: Declare and Lookup Resource Reference
Option 1
This can be done by declaring a resource-ref in your web deployment descriptor (WEB-INF/web.xml):
<resource-ref>
<description>My Data Source.</description>
<res-ref-name>jdbc/MyDataSource</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
Within your code, you can then lookup this resource using the JNDI name java:comp/env/jdbc/MyDataSource:
dataSource = (DataSource) new InitialContext().lookup("java:comp/env/jdbc/MyDataSource");
This JNDI name will not change regardless of the server where the application is deployed.
Option 2
Alternatively, starting in Java EE 5 (Servlet 2.5), this can be done even easier within your code using the #Resource annotation. This eliminates the need for configuring the resource-ref in your web deployment descriptor (web.xml) and prevents the need to perform an explicit JNDI lookup:
public class MyServlet extends HttpServlet {
#Resource(name = "jdbc/MyDataSource")
private DataSource dataSource;
#Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// dataSource may be accessed directly here since the container will automatically
// inject an instance of the data source when the servlet is initialized
}
This approach has the same results as the previous option, but cuts down on the boilerplate code and configuration in your assembly.
Step 2: Map Resource Reference to Data Source
Then, you will need to use your application server's proprietary approach for mapping the resource reference to the physical data source that you created on the server, for example, using JBoss's custom deployment descriptors (WEB-INF/jboss-web.xml):
<?xml version="1.0" encoding="UTF-8"?>
<jboss-web>
<resource-ref>
<res-ref-name>jdbc/MyDataSource</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<jndi-name>java:/MyDataSource</jndi-name>
</resource-ref>
</jboss-web>
Or, for example, using Tomcat's context.xml:
<Resource name="jdbc/MyDataSource" . . . />

You can add to your data source definition the 'jndi-name' tag:
jndi-name - the JNDI name under which the DataSource should be bound.
You can find data source documentation on JBoss wiki: ConfigDataSources