Java Core Classes and Threads

Hashtable relies on both equals() and hashCode() to store and locate keys. If you override equals() but not hashCode(), equal objects will have different hash codes, preventing Hashtable from finding them. Circular references can also cause infinite loops or incorrect behavior during lookup.

The claimed answer is C. When a commandLink or commandButton action method returns null, JSF executes the action method but then re-renders the current view instead of navigating to a different page. Option A and B are incorrect because no exception is thrown. Option D is misleading - it's not just 'same page', it's explicitly re-rendering the current view after action execution.

The processDecodesWithoutValidation method in JSF does exactly what its name suggests: it executes the Apply Request Values phase and decodes parameters without running validation. This is useful for scenarios where you want to process submitted data but skip validation logic. The method will handle RuntimeExceptions appropriately, but its key characteristic is bypassing the validation phase for immediate components.

OPEN_FORM is the correct method when you need to use both the calling form and called form simultaneously. CALL_FORM replaces the calling form and control returns only after the called form exits, while NEW_FORM replaces the calling form completely without returning.

The Struts 2 exception handling mechanism primarily handles unchecked exceptions (RuntimeException and its subclasses). Checked exceptions need to be caught and handled by the application code or wrapped in runtime exceptions. The exception mapping in struts.xml works with unchecked exceptions.

In Java's exception hierarchy, Throwable is the base class for all throwable objects. Exception inherits directly from Throwable, while Error is a separate subclass of Throwable for serious system errors that applications typically shouldn't catch.

StackOverflowError and OutOfMemoryError are both subclasses of java.lang.Error, not Exception. Errors represent serious problems that applications should not typically catch - they indicate JVM-level issues rather than application logic problems.

After an exception is handled and no references to the exception object remain, it becomes eligible for garbage collection like any other dereferenced Java object. It does not remain permanently on the stack.

NullPointerException extends RuntimeException, making it an unchecked exception. This means developers aren't required to catch or declare it - it typically indicates programming errors like attempting to use a null reference where an object is required.

GetROProperty (Get Run-Time Object Property) is the QTP/UFT method used to retrieve the current property value of a test object from the application during a run session. GetTOProperty retrieves properties from the test repository, and SetROProperty is not a valid method.

Session.Abandon() is the correct method to explicitly terminate a user's session in ASP.NET. It ends the current session, releases session resources, and fires the Session_End event. The other methods (Close, Discard, Exit) do not exist in the Session API.

Once a Java thread completes its execution (exits its run() method) or is terminated, its state becomes 'TERMINATED' (dead). In JVM, you cannot restart a dead thread; attempting to call start() on it again will throw an IllegalThreadStateException.

StringBuffer is synchronized (thread-safe) while StringBuilder is not. Both classes are mutable - they can be modified after creation. StringBuilder is faster when you don't need thread safety.

A Thread can be created either by extending the Thread class or by implementing the Runnable interface. Option A is wrong because Thread is a class, not an interface. Option D is wrong - we can and do create Threads programmatically.