02 Prelim CP2 (continuation)

Question 1

The (1)_____ keyword can be used to allow
declaration of static variables and
methods that belong to the (2)_____ instead of a (3)______ instance (such as the main method):

Answer 1

1. static
2. Class
3. Specific

Question 2

What is the static variable in this code:

public class StaticExample {

 static int staticNumber = 10;

 static void staticMethod() {
     System.out.println("Static number is: " + staticNumber)
 }

 public static void main (String[] args) {

 StaticExample.staticMethod();

 System.out.print(staticNumber):

 } }

Answer 2

staticNumber

Question 3

What is the method in this code:

public class StaticExample {

 static int staticNumber = 10;

 static void staticMethod() {
     System.out.println("Static number is: " + staticNumber)
 }

 public static void main (String[] args) {

 StaticExample.staticMethod();

 System.out.print(staticNumber):
 }

}

Answer 3

staticMethod()

Question 4

What is the output of this code:

public class StaticExample {

 static int staticNumber = 10;

 static void staticMethod() {
     System.out.println("Static number is: " + staticNumber)
 }

 public static void main (String[] args) {
 StaticExample.staticMethod();

 System.out.print(staticNumber):
 }

}

Answer 4

Output:

Static number is: 10
10

Question 5

(1)_______ refers to the process of creating an actual object (or instance) from a class. In object-oriented programming, a class is like a blueprint, and
(2)______ the class means creating an object based on that blueprint.

Answer 5

1. Instantiation
2. Instantiating

Question 6

instantiating the class means….

Answer 6

creating an object based on that blueprint.

Question 7

(1)________Instantiation allows you to reuse the same class multiple times to create different objects with potentially different states. This reduces code (2)_______.

Answer 7

1. Reusability
2. Redundancy

Question 8

What is the output:

public class InstanceExample {

// Instance variable (not static)
 int instanceNumber = 10;

 // Instance method (not static)
 static void InstanceMethod() {
     System.out.println("Instance number is: " + instanceNumber)
 }

 public static void main (String[] args) {

 // Create an object (instatiate the class)
 instanceExample example = new instanceExample();

 // call the instance method using the object 
 example.instanceMethod():
 } }

Answer 8

Output:

Instance number is: 10

Question 9

What is the output:

public class sample {

 static int count = 0 ; // shared by all

 public void increment () {
      count ++; // increment shared variable }
 
 public static void main (String[] args) {

      sample A = new Sample(); // first instance
      sample B = new Sample(); // second instance 

 A.increment() // count becomes 1
 System.out.println("A.count");
 System.out.println("Object A: " + A.count ); // prints 1

 B.increment() // count becomes 2
 System.out.println("Object B: " + B.count ); //prints 2
 System.out.println("Object A: " + A.count ); // prints 2

 } }

Answer 9

A.count
Object A: 1
Object B: 2
Object A: 1

Question 10

For example, we could define a method named sum that returns the sum of its two (2) parameters:

Syntax:
static int sum(int val1, int val2) {
return val1 + val 2 ;
}

Answer 10

Return Type

Question 11

Return Method (Return type)
What is the output:

class Myclass {
static int sum(int val1, int val2) {
return val1 + val2;
}

 public static void main(String[ ] args) {
 int x = sum(2,5);
 System.out.println(x);

 } }

Answer 11

Output: 7

Question 12

What keyword should you use if you do not want your method to return anything?

Answer 12

Void

Question 13

Return Method Outputs:

// Sample 1
static int returnFive()
return 5;

// Sample 2 (has a parameter) {
static void sayHelloTo(String name)
System.out.println(“Hello”+ name)
}

Use john

// Sample 3
static void sayHello() {
system.out.println(“Hello world!”);
}

Answer 13

S1: 5
S2: Hello John
S3: Hello World!

Question 14

Fill in the blanks to declare an integer and pass it as a parameter to the test() method:

class MyClass {
public static void main(String [] args) {
____ x = 10;
test(__);
}

 static void test(int x) {
      System.out.println(x);
 } }

Answer 14

int x = 10;
test(x) ;

Question 15

______ are basically variables within a class:

Answer 15

Attributes

Question 16

Access Modifiers

Answer 16

1. default
2. public
3. protected
4. private

Question 17

Access Modifier

public static void main(Stringl ] args)

______ is an access modifier, it is used to set the levels of access.

Answer 17

public

Question 18

______ a variable or method declared with no access control modifier is available to any other class in the same package

Answer 18

default

Question 19

□ _______ - accessible from any other class.

Answer 19

public

Question 20

□ _______ - provides the same access as the default access modifier, with the addition that subclasses can access protected methods and variables of the superclass.

Answer 20

protected

Question 21

□ _______ - accessible only within the declared class itself.

Answer 21

private

Question 22

______ and ______ are used to effectively
protect your data when creating classes.

Answer 22

Getters
Setters

Question 23

> The _____ _____ returns the value of the
attribute.

Answer 23

Getter method

Question 24

> The _____ ____ takes a parameter and
assigns it to the attribute.

Answer 24

Setter method

Question 25

Getters start with (1)______, followed by the variable name, with the first letter of the variable name (2)_____.

Setters start with (3)___, followed by the variable name, with the first letter of the variable name (2)_______.

Answer 25

1. get
2. Capitalized
3. set