Computer Knowledge

Programming Fundamentals

2,381 Questions

Programming fundamentals form the core logic of software development and computer science. This includes variable declarations, pointer assignments, loop iterations, and exception handling. These technical topics are regularly tested in computer knowledge and IT officer competitive examinations.

Variables and arraysPointer assignmentsLoop iterationsException handling blocksCompile time errorsFunction references

Programming Fundamentals Questions

Multiple choice

Suppose in the declaration section of a PL/SQL block, you create but do not initialize a NUMBER variable. What will be the initial value of the variable when the block is executed?

  1. 0

  2. NULL

  3. Depends on the scale and precision of the datatype.

  4. Without initialization, a variable cannot be used in the executable section of the block.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In PL/SQL, any scalar variable (NUMBER, VARCHAR2, DATE, etc.) that is declared but not initialized automatically gets NULL as its initial value. Option A is incorrect because 0 would need explicit initialization. Option C is wrong because NULL behavior is consistent across scale/precision. Option D is false because uninitialized variables can be used - they'll just be NULL until assigned.

Multiple choice

A Ref cursor can be passed from one procedure to another

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

REF cursors in PL/SQL are cursor variables that can be passed between procedures and functions. Unlike static cursors, REF cursors are dynamic and can be opened for different queries at runtime and shared across program units.

Multiple choice

The database EMPLOYEES table has a foreign key constraint referencing the DEPARTMENTS table. A Human Resource application is being developed. HR clerks use the Employees form to query, update, and insert employee records. They occasionally attempt to add an employee who is in a new department that has not yet been entered into the database. When this happens, they receive an error indicating that the parent record cannot be found, so they cannot commit the employee record. The HR clerks have requested that a button be placed on the form to enable them to invoke the Departments form to enter the new department and save it independently. They want to be able to return to the Employees form and decide whether or not to save the new employee record. How should the When-Button-Pressed trigger be coded to achieve this?

  1. CALL_FORM('Departments);

  2. CALL_FORM('Departments',NO_HIDE);

  3. OPEN_FORM('Departments');

  4. OPEN_FORM('Departments', ACTIVATE, SESSION);

  5. OPEN_FORM('Departments', NO_ACTIVATE, NO_SESSION);
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

OPEN_FORM with the ACTIVATE and SESSION parameters opens the Departments form in a separate session while keeping the Employees form available. This allows clerks to enter and save the new department independently, then return to decide about the employee. CALL_FORM would replace the form entirely, and NO_ACTIVATE/NO_SESSION would not provide the needed independence.

Multiple choice

Tom is developing a Human Resources form for HR clerks to insert, update, and delete records from the EMPLOYEES table. When the user commit records, Forms displays the default informative message 'FRM-40400: Transaction complete: records applied and saved.' He wants to replace that with the message 'Records inserted:', 'Records updated:', 'Records deleted:', Which of the following triggers must be created to modify or to accomplish this?

  1. On-Message only

  2. Post-Commit and On-Message

  3. Post-Database-Commit and On-Message

  4. Post-Insert, Post-Update, Post-Delete, and On-Message

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

To replace the default Forms message with specific counts for insert/update/delete operations, you need Post-Insert, Post-Update, and Post-Delete triggers to capture counts after each operation type, plus an On-Message trigger to intercept and replace the FRM-40400 message. Post-Database-Commit fires too late (after transaction completes), and Post-Commit doesn't distinguish between operation types.

Multiple choice

The DBA added a STATE column defined as VARCHAR2(2) to the State table. This column will contain two-letter state abbreviations because the State table is quite large, storing complete state names would waste space in the database. The DBA asks JOHN to add a corresponding State item to the State block of the Geographical Management form. JOHN opened the Layout Editor of the Geographical Management form and created a list item on the canvas in the State block. In the Property Palette for the list item, he changed the Name property to State and the Database Item property to Yes. He then open the Elements in List property and add some state abbreviations and names to the list, as shown in the exhibit. When he ran the form to test it, after selecting a value from the list and clicking Commit, he received an FRM error. Its corresponding database error is the following: ORA-01401: inserted value too large for column What should he do to correct this problem?

  1. Have the DBA increase the column width in the database.

  2. Change the List Style property for the State item to Combo Box.

  3. Change the List Style property for the State item to T-list.

  4. Change the elements in the list of the State item so that the list elements are the state names and the list element values are the state abbreviations.t.

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The error occurs because John is storing full state names in the list elements, but the database column is VARCHAR2(2) expecting only abbreviations. The solution is to use state names as display labels (what users see) while mapping them to 2-character abbreviations as actual values stored in the database.

Multiple choice

SMITH was running a form in the debug mode and begins to step through the code of a lengthy subprogram. After stepping through a few lines of its code, he realized that the error came not from the code in that particular subprogram but from code that is executed after it. At this point, how can he jump to the next line of code after the call to the subprogram?

  1. Clicking Step Over to step over the execution of the subprogram

  2. Opening the Stack panel, selecting the previous stack frame, and clicking Go

  3. Clicking Step Out to resume stepping through code after the subprogram is called

  4. HE cannot do this in the same debug session. He should click Stop, set a breakpoint immediately after the subprogram code is called, and run the form in debug mode again
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Step Over executes the entire subprogram without stepping through its internal lines, then returns control to the line immediately after the subprogram call. This is exactly what SMITH needs when he realizes the error is in code after the subprogram, not within it.

Multiple choice

TOM wants to create a new data block. He clicked the Data Blocks node in the Object Navigator, and then clicked Create to invoke the Create Data Block dialog box. As he clicked through the pages of the wizard, Create Relationship option appears. Which of the following statements hold true about the form?

  1. The block he is creating is based on a view

  2. The block he is creating is based on a stored procedure

  3. The form contains at least one block in addition to the block he is creating

  4. In addition to the block he is creating, the form contains at least two other blocks that are master detail blocks

  5. The block he is creating is based on a table that has at least one foreign key relationship to another table
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice

Which of the following statements is/are true?

  1. TreeMap is the class of Map interface.

  2. HashMap inherits SortedMap interface.

  3. HashMap is not synchronised.

  4. Only (1) and (3) are true.

  5. (1), (2) and (3) all are true.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, both the statements are true.

Multiple choice

class X2 { public X2 x; public static void main(String [] args) { X2 x2 = new X2(); /* Line 6 / X2 x3 = new X2(); / Line 7 / x2.x = x3; x3.x = x2; x2 = new X2(); x3 = x2; / Line 11 */ doComplexStuff(); } } after line 11 runs, how many objects are eligible for garbage collection?

  1. 0

  2. 1

  3. 2

  4. 3
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is an example of the islands of isolated objects. By the time line 11 has run, the objects instantiated in lines 6 and 7 are referring to each other, but no live thread can reach either of them.

Multiple choice

Which two of the following are legal declarations for nonnested classes and interfaces?

  1. final abstract class Test {}
  2. public static interface Test {}
  3. final public class Test {}
  4. protected abstract class Test {}
  5. protected interface Test {}
  6. abstract public class Test {}

  1. 1 and 4

  2. 2 and 5

  3. 3 and 6

  4. 4 and 6
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(3), (6). Both are legal class declarations. (1) is wrong because a class cannot be abstract and final—there would be no way to use such a class. (2) is wrong because interfaces and classes cannot be marked asstatic. (4) and (5) are wrong because classes and interfaces cannot be marked asprotected.

Multiple choice

Which statement is true about a static nested class?

  1. You must have a reference to an instance of the enclosing class in order to instantiate it.

  2. It does not have access to nonstatic members of the enclosing class.

  3. It's variables and methods must be static.

  4. It must extend the enclosing class.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Option B is correct because a static nested class is not tied to an instance of the enclosing class, and thus can't access the nonstatic members of the class (just as a static method can't access nonstatic members of a class). Option A is incorrect because static nested classes do not need (and can't use) a reference to an instance of the enclosing class. Option C is incorrect because static nested classes can declare and define nonstatic members. Option D is wrong because it just is. There's no rule that says an inner or nested class has to extend anything.

Multiple choice

Which constructs an anonymous inner class instance?

  1. Runnable r = new Runnable() { };

  2. Runnable r = new Runnable(public void run() { });

  3. Runnable r = new Runnable { public void run(){}};

  4. System.out.println(new Runnable() {public void run() { }});
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

D is correct. It defines an anonymous inner class instance, which also means it creates an instance of that new anonymous class at the same time. The anonymous class is an implementer of the Runnable interface, so it must override the run() method ofRunnable. A is incorrect because it doesn't override the run() method, so it violates the rules of interface implementation. B and C use incorrect syntax.

Multiple choice

public void test(int x) { int odd = 1; if(odd) /* Line 4 */ { System.out.println(odd); } else { System.out.println(even); } }

Which statement is true?

  1. Compilation fails.

  2. odd will always be the output.

  3. even will always be the output.

  4. odd will be the output for odd values of x, and even for even values.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The compiler will complain because of incompatible types (line 4), the if expects a boolean but it gets an integer.