ClassCastException in Stateful Session-Bean
I'm a beginner and would like to run some JBoss EJB 3.0 examples:
Calculator (Stateless SessionBean) - OK!
ShoppingCart (Stateful SessionBean) - ClassCastException
Environment:
o Java 1.5.0_09
o IntelliJ IDEA 6.0.4
o JBoss 4.0.5 AS (JEMS Installer with ejb3)
o Windows XP SP2
Interfaces:
@Local
@Remote
public interface Calculator {
int add(int x, int y);
int subtract(int x, int y);
}
@Local
@Remote
public interface ShoppingCart {
void buy(String product, int quantity);
HashMap<String, Integer> getCartContents();
}
SessionBeans:
@Stateless
public class CalculatorBean implements Calculator {
public int add(int x, int y) {
return x + y;
}
public int subtract(int x, int y) {
return x - y;
}
}
@Stateful
public class ShoppingCartBean implements ShoppingCart {
private HashMap<String, Integer> cart;
public ShoppingCartBean() {
cart = new HashMap<String, Integer>();
}
public void buy(String product, int quantity) {
if (cart.containsKey(product)) {
int currq = cart.get(product);
currq += quantity;
cart.put(product, currq);
} else {
cart.put(product, quantity);
}
}
public HashMap<String, Integer> getCartContents() {
return cart;
}
}
Client:
public class Client {
public static void main(String[] args) throws Exception {
System.setSecurityManager(new RMISecurityManager());
InitialContext ctx = new InitialContext();
ctx.addToEnvironment(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
ctx.addToEnvironment(Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
ctx.addToEnvironment(Context.PROVIDER_URL, "jnp://localhost:1099");
Calculator calculator = (Calculator) ctx.lookup("MyApplication/CalculatorBean/remote");
System.out.println("1 + 1 = " + calculator.add(1, 1));
System.out.println("1 - 1 = " + calculator.subtract(1, 1));
}
}
public class Client {
public static void main(String[] args) throws Exception {
System.setSecurityManager(new RMISecurityManager());
InitialContext ctx = new InitialContext();
ctx.addToEnvironment(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
ctx.addToEnvironment(Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
ctx.addToEnvironment(Context.PROVIDER_URL, "jnp://localhost:1099");
ShoppingCart cart = (ShoppingCart) ctx.lookup("MyApplication/ShoppingCartBean/remote");
}
}
Policy:
grant {
permission java.security.AllPermission;
};
JBoss LOG:
[...] 16:34:50,404 INFO [JmxKernelAbstraction] installing MBean: jboss.j2ee:ear=MyApplication.ear,jar=MyEjb.jar,name=ShoppingCartBean,service=EJB3 with dependencies: 16:34:50,419 INFO [EJBContainer] STARTED EJB: org.jboss.tutorial.stateful.bean.ShoppingCartBean ejbName: ShoppingCartBean 16:34:50,466 INFO [SimpleStatefulCache] Initializing SimpleStatefulCache with maxSize: 100000 timeout: 300 for jboss.j2ee:ear=MyApplication.ear,jar=MyEjb.jar,name=ShoppingCartBean,service=EJB3 16:34:50,466 INFO [JmxKernelAbstraction] installing MBean: jboss.j2ee:ear=MyApplication.ear,jar=MyEjb.jar,name=CalculatorBean,service=EJB3 with dependencies: 16:34:50,466 INFO [EJBContainer] STARTED EJB: org.jboss.tutorial.stateless.bean.CalculatorBean ejbName: CalculatorBean [...]
Command:
java \ -Djava.security.policy=java.policy \ -classpath jbossall-client.jar;jboss-aop-jdk50-client.jar" \ org.jboss.tutorial.stateless.client.Client 1 + 1 = 2 1 - 1 = 0 java \ -Djava.security.policy=java.policy \ -classpath jbossall-client.jar;jboss-aop-jdk50-client.jar" \ org.jboss.tutorial.stateful.client.Client Exception in thread "main" java.lang.ClassCastException: javax.naming.Reference at org.jboss.tutorial.stateful.client.Client.main(Client.java:20)
