Some Important Questions with Answers

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Some Important Questions with Answers

1. Which window is used to designed the form.
Ans: Design window

2. Which window contains the Swing Controls components.
Ans: Palette window

3. What is the most suitable component to accept multiline text.
Ans : Text Area

4. What will be the output of the following command?
Learning.concat("Java")
Ans : Error

5. What will be the output of the following command?
"Learning".concat("Java")
Ans: LearningJava

6. Name the different list type controls offered by Java Swing.
Ans: (i) jListBox
(ii) jComboBox

7. Name any two commonly used method of ListBox.
Ans: getSelectedIndex() and getSelectedValue()
8. Write code to add an element (“New Course”) to a list (SubList) at the beginning of the list.
Ans: SubList.add(0,”New Course”);

9. Describe the three common controls. Also give some of their properties.
Ans:
(i) jButton text,icon
(ii) jLabel text,border
(iii) jTextField text,font

10. By default a combo box does not offer editing feature.How would you make a combo box editable.
Ans: By setting its editable property to false.

11. Write Name the component classes of Swing API for the following components-
(a) frame (b) button
Ans:(a)JFrame(b)JButton

12. What is the name of event listener interface for action events ?
Ans: ActionPerformed

13. What does getpassword() on a password field return ?
Ans: a character array

14. What is event driven programming?
Ans:This programming style responds to the user events and is driven by the occurrence of user events.

15. What are containers? Give examples.
Ans: Containers are those controls inside them e.g., frame (JFrame), Panel (JPanel), label (JLabel)
etc. are containers.

16. Which method of list is used to determine the value of selected item, if only one itm is selected.
Ans: getSelectedValue()

17. Which type of storage is provided by variables.
Ans: temporary

18. What will be the output of the following code segment:
String firstName = "Johua ";
String lastName = "Yacomo";
String fullName = firstName + lastName;
jTextField1.setText("Full Name: ");
jTextField2.setText (fullName);
Ans: Full Name:
 JohuaYacomo

19. Which expression is used to print the value of a variable "x" of type int.
Ans: jTextField1.setText("x = " + x);

20. The statement i++; is equivalent to
Ans :i=i+1

21. Name the primitives datatypes in java.
Ans: Numeric type , Fractional type, Character type and Boolean type.

22. Which events gets fired when a user click a JButton and JRadioButton.
Ans: ActionPerformed

23. Which of the following is a selection construct ?
a. do while Loop b. for Loop c. while Loop d. None of these
Ans: none of these

24. What will be used if there are two or more possible options.
Ans: is else if and switch

25. Name the loop that never ends.
Ans: infinite loop
26. Which braces is used to enclose statements in a block statement.
Ans: { } Curly braces

27. Which of the following is an exit controlled loop?
a. for loop b. do while Loop
c. while loop d. none of these
Ans: do while loop

28.Which process is used to translate a task into a series of commands that a
computer will use to perform that task.
Ans: Project design

29. Which of the following component is the best suited to accept the country of the
user?
A. List
B. Combo box
C. Radio button
D. Check box

Ans: List and combo box

30. Which construct will be used to find the sum of the first 10 natural numbers?
Ans: for loop


31. Which of the following is not a good programming guideline?

Ans : Using text fields to accept input of marital status