EJB and COBOL Programming Quiz

The standard ECL (Exec Control Language) statement format begins with @LABEL: followed by the COMMAND, then any OPTION(S), then the FIELD specifications, and ends with an optional COMMENT. The format is: @LABEL:COMMAND,OPTION(S)FIELD1,FIELD2..COMMENT. This places the command immediately after the label colon, which is the correct syntax.

In standard COBOL, the verbs ACCEPT, MOVE, and STRING are all valid COBOL verbs. FIND is not a standard COBOL verb - it's typically used in database systems like SQL or in some mainframe query utilities, but not in core COBOL programming. This makes 'FIND' the correct answer to what 'is not a COBOL verb'.

FURPUR is a Unisys software utility that stands for File Utility Routines/Program Utility Routines. This is a system program that handles file operations, processes user runs, manages system resources, and performs I/O operations. Option C correctly expands the acronym with 'Routines' for both components.

The description matches the Exec program (often called 'Exec' or 'executive') in Unisys systems. This is the system software that manages user runs, controls files, handles system resources, and performs I/O operations. While FURPUR is a utility program and ECL is a control language, 'Exec' is the overall system software that performs these supervisory functions.

According to COBOL programming standards (especially in mainframe environments), the PROGRAM-ID paragraph must specify an 8-character descriptive name. This is a specific naming convention requirement - exactly 8 characters, not 'at least 8' or '8 or more'. Option B correctly states 'must be an 8-character descriptive name'.

EJB containers provide core enterprise services: security management for authentication/authorization and transaction management for JTA support. Load balancing and fault tolerance are not part of the standard EJB container services.

EJB 2.0 spec restricts beans to managed container environments: they cannot act as socket servers (C) because the container manages all network resources, and cannot use java.io (D) to prevent direct file system access. Option A is false - beans can use Sockets (as clients), and B is false - instance variables can be static/final.

Deployment descriptor must be a fully-qualified Java type (primitive wrappers or Strings). int and short are primitives - use java.lang.Integer or java.lang.Short instead. java.lang.Boolean and java.lang.Character are valid fully-qualified class names.

All listed statements are FALSE: home interfaces can be reused (not single-use), session beans share one EJBHome (not per-instance), InitialContext narrowing is implementation-specific (not universal), and local clients DO need home interfaces for certain operations. Therefore F (None of the above) is correct.

In EJB, remote references (R) can be passed to local clients (L) because remote interfaces are designed for network serialization. However, local references (L) cannot be passed to remote clients - local interfaces are not serializable and exist only within the same JVM. Option C correctly notes that whether L can call methods on R depends on R's actual type and location - this isn't about the local/remote client distinction but about the specific object being referenced. L can always call methods on B since that's its designated session bean.

A stateful bean is instantiated when the client calls create on its home interface, and a stateless bean’s create call may not result in a new instance because the container can pool instances. The other statements misstate removal semantics or client capabilities.

The isCallerInRole() method requires an established security context, which is available only after setSessionContext() has been called. For stateless session beans, ejbCreate() is called BEFORE setSessionContext(), so the security context isn't available yet. For stateful session beans, setSessionContext() is called BEFORE ejbCreate(), making the security context available. The setSessionContext() method itself cannot call isCallerInRole() because the context is still being initialized.

The EJB container is responsible for calling lifecycle methods like ejbCreate() when a client invokes a create method. The container also provides implementations of context interfaces like EJBContext (specifically SessionContext for session beans). The bean developer is responsible for implementing the SessionBean interface, setSessionContext(), and ejbRemove() methods - these are part of the bean class code.

Option A is incorrect because the container manages stateful session beans in a pool - ejbRemove() makes the instance eligible for pooling, not immediate garbage collection. Option B is incorrect because stateful session beans can be created through various means including dependency injection or lookups, not just explicit client create calls. Option C is incorrect because security context isn't available in ejbCreate() for stateless beans. Option D is correct - setSessionContext() is called exactly once per bean instance when it's first created.

During setSessionContext(), the bean is still being initialized and doesn't have access to other beans or their methods. The security context and environment resources are not yet fully available. In ejbCreate(), ejbRemove(), and ejbPassivate(), the bean is fully initialized and can interact with other beans. This restriction applies specifically to the context initialization phase.

When a client invokes a session bean that no longer exists, the exception depends on the client type. Local clients receive javax.ejb.NoSuchObjectLocalException. Remote clients receive java.rmi.NoSuchObjectException (a RemoteException subtype). Option B's NoSuchObjectException and Option C's RemoveException are incorrect exception types. Option D's ObjectNotFoundException is typically for database operations, not EJB invocations.

The SessionContext interface defines methods for transaction control and EJB home access, including getRollbackOnly() and getEJBHome(). Lifecycle methods such as ejbCreate, ejbActivate, and setSessionContext belong to SessionBean or its ancestors, not SessionContext, so they are incorrect.