Some of your code might use EJB session beans through JNDI lookup. To make this code find your session beans in your unit tests, you can replace the initial context quite easily. This is an example of how it can be done. public class ReplaceInitialContext extends InitialContext implements InitialContextFactory { static ReplaceInitialContext instance = null; public ReplaceInitialContext() throws NamingException { super(false); } public static ReplaceInitialContext getInstance() throws NamingException { if(instance == null) { System.setProperty("java.naming.factory.initial",ReplaceInitialContext.class.getName()); instance = new ReplaceInitialContext(); } return instance; } @Override protected void init(Hashtable environment) throws NamingException { } @Override public Object lookup(String name) throws NamingException { return "Hello"; }