Could not dereference object

[lasanac]

Hello,

I keep this error:


javax.naming.NamingException: Could not dereference object [Root exception is java.lang.NullPointerException]
at org.jnp.interfaces.NamingContext.getObjectInstanceWrapFailure(NamingContext.java:1152)
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:707)
at org.jnp.interfaces.NamingContext.lookup(NamingContext.java:589)
at javax.naming.InitialContext.lookup(InitialContext.java:351)
at com.kt.dao.DBConnection.doConnection(DBConnection.java:46)
at com.kt.dao.MakeConnectionTest.main(MakeConnectionTest.java:17)
Caused by: java.lang.NullPointerException
at org.jnp.interfaces.NamingContextFactory.getObjectInstance(NamingContextFactory.java:83)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304)
at org.jnp.interfaces.NamingContext.getObjectInstance(NamingContext.java:1127)
at org.jnp.interfaces.NamingContext.getObjectInstanceWrapFailure(NamingContext.java:1144)
... 5 more



I am running on JBoss 4.2.0GA
using JDK 1.5
DB is MySQL5.0
here is my code:

public Hashtable doEnvironment(){

Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
env.put(Context.PROVIDER_URL, "jnp://localhost:1099");
return env;
}

public String doConnection(Hashtable env){

try{


Reference ref = new Reference("javax.sql.DataSource", "org.jnp.interfaces.NamingContextFactory", null);
System.out.println("step 1");
Context ctx= new InitialContext(env);
ctx.rebind("java:MySQLDS", ref);
//ctx = new InitialContext();
System.out.println("step 2");
DataSource ds = (DataSource)ctx.lookup("java:MySQLDS");

System.out.println("step 3 " + obj.getClass().getName().toString());


}
catch(Exception ex){
ex.printStackTrace();
}


return null;


It nevers gets to step 3...

Is there something wrong with what I am doing? Please help


LC

[jaikiran]

What is client application trying to do? Especially, what's the purpose of using

ctx.rebind("java:MySQLDS", ref);

[lasanac]

I am just testing the back end of the application. Currently I used:

ctx.rebind("java:MySQLDS", ref);

as it got rid of another problem that I had earlier. That was a CastException for Reference object. I did retest it without that line and got the same error.

New Code:

System.out.println("step 1");
Context ctx= new InitialContext(env);
System.out.println("step 2");
DataSource ds = (DataSource)ctx.lookup("java:MySQLDS");
System.out.println("step 3 ");

[lasanac]

Please disregard my last post!!!!!!


When I don't use:

ctx.rebind("java:MySQLDS", ref);


I get the following error:

step 1
step 2
java.lang.ClassCastException: javax.naming.Reference
at com.kt.dao.DBConnection.doConnection(DBConnection.java:43)
at com.kt.dao.MakeConnectionTest.main(MakeConnectionTest.java:17)