In my client :
Context initContext = new InitialContext();
			Context myEnv = (Context)initContext.lookup("java:comp/env");
			//	Valeur de KOKO
			String kiki = (String)myEnv.lookup("KIKI");
			System.out.println("KIKI vaut : " + kiki);

In my DD :
<!-- Access in code using JNDI lookup("java:/comp/env/KIKI") -->
      <env-entry>
		<env-entry-name>KIKI</env-entry-name>
		<env-entry-type>java.lang.String</env-entry-type>
		<env-entry-value>COCO</env-entry-value>
      </env-entry>

Error :
javax.naming.NameNotFoundException: env
	at org.objectweb.jonas.naming.CompNamingContext.lookup(CompNamingContext.java:158)
	at org.objectweb.jonas.naming.CompNamingContext.lookup(CompNamingContext.java:198)
	at org.objectweb.jonas.naming.java.javaURLContext.lookup(javaURLContext.java:176)
	at javax.naming.InitialContext.lookup(InitialContext.java:347)
	at pu.enseignantClient.main(enseignantClient.java:83)