Java Core Classes and Threads

The code calls run() directly on each Pmcraven object instead of start(). This means the code executes sequentially in the main thread, not as separate threads. Each run() method prints the thread name twice before returning, producing 'one one' then 'two two'.

The Set interface prevents duplicate elements. When attempting to add an element already present in the set, the add method simply returns false and leaves the set unchanged. It does not throw exceptions or cause compile-time errors.

To answer this question, the user needs to understand the basic functionality of the Set collection in Java.

Option A is incorrect. When attempting to add an element to a Set that already exists in the Set, an exception is not thrown. Instead, the Set simply ignores the duplicate element and does not add it to the collection.

Option B is correct. The add method of a Set returns a boolean value of false if the element being added already exists in the Set. This is because Sets do not allow duplicate elements.

Option C is incorrect. Sets are designed to contain only unique elements. If an element already exists in the Set, it will not be added again. Therefore, a Set cannot contain elements that return duplicate values from a call to the equals method.

Option D is incorrect. Duplicate values will not cause an error at compile time. Instead, the Set will simply ignore the duplicate value when the code is executed.

Therefore, the correct answer is:

The Answer is: B. The add method returns false if you attempt to add an element with a duplicate value.

Calling run directly on a Thread executes the method synchronously in the current thread instead of starting a new thread of execution. Therefore, pm1 completes its loop printing one twice before pm2 starts its loop printing two twice.

In Pega PRPC, invoking the Activity-End method immediately terminates the current activity as well as all calling activities in the execution stack. It prevents the system from returning control to the parent/calling activity. Conversely, the Exit-Activity method only terminates the current activity and returns control to the caller.

Implementing the Runnable interface is preferred over extending the Thread class in Java because Java does not support multiple inheritance. By implementing an interface, the class remains free to inherit from another class. This approach also promotes better separation of concerns between the task execution logic and the thread mechanism.

Implementing Runnable interface is preferred over extending Thread class because Java supports only single inheritance - by implementing Runnable, your class can still extend another class if needed. It also separates the task logic from the thread execution mechanism, following better object-oriented design principles. Extending Thread should only be used when you need to override Thread methods other than run().

Activity-End terminates both the current activity and the calling activity, then continues with the next activity on the requestor's list. End-Activity, Exit-Activity, and Activity-Exit are not valid PRPC method names.

Obj-Save has a Write-Now checkbox that writes immediately to the database, while Obj-Delete has an Immediate checkbox for the same purpose. Both bypass the normal Commit method requirement when these checkboxes are selected.

Activity-End is the correct Pega method that terminates the current activity and returns control to the calling activity, which then continues with the next activity on the requestor's list. This is essential for controlling flow in Pega processes. The naming convention places the object (Activity) before the action (End).

In Pega, Obj-Save has a Write-Now checkbox that causes immediate database write, while Obj-Delete has an Immediate checkbox for the same purpose. Both bypass the standard Commit method queue and perform the database operation instantly. Remembering which method uses which checkbox name is key.

In JSP, only jspInit() and jspDestroy() can be overridden by developers. The _jspService() method is generated by the container and cannot be overridden (it's marked final in the generated servlet). getParameter() is a method of ServletRequest interface, not a JSP lifecycle method.

When a web browser loads an applet, it calls the init() method first - this is where one-time initialization happens. The browser then calls start() to begin execution, and may call paint() when the display needs rendering. The main() method is NOT used in applets - that's for standalone applications.

Wicket uses POST as the default method for form submission. POST is preferred for forms because it can send larger amounts of data and doesn't expose parameters in the URL. GET can be explicitly configured but is not the default.

public, static, and void are reserved keywords in Java used for access control, modifiers, and return types. String is a class name (identifier) and main is a method name (identifier), not keywords.