Java quiz 1

Number of primitive data types in Java are?

• 6

• 7

• 8

• 9

What is the size of float and double in java?

• 32 and 64

• 32 and 32

• 64 and 64

• 6 and 32

Which of the following option leads to the portability and security of Java?

• 1. Bytecode is executed by JVM

• 1. The applet makes the Java code secure and portable

• 1. Use of exception handling

• 1. Dynamic binding between objects

Which of the following is not a Java features?

• 1. Dynamic

• 1. Architecture Neutral

• 1. Use of pointers

• 1. Object-oriented

Evaluate the following Java expression, if x=3, y=5, and z=10:

++z + y - y + z + x++

• 24

• 23

• 20

• 25

Answer explanation

In the above expression, ++z means that the value will first increment by 1, i.e. 12. Now, evaluate the statement by putting the values of x, y, and z. On evaluating the expression, we get 25, as shown below.

++z +y -y +z + x++
11 + 5 - 5 + 11 + 3 = 25

Which of the following for loop declaration is not valid?

• 1. for ( int i = 99; i >= 0; i / 9 )

• 1. for ( int i = 7; i <= 77; i += 7 )

• 1. for ( int i = 20; i >= 2; - -i )

• 1. for ( int i = 2; i <= 20; i = 2* i )

When an array is passed to a method, what does the method receive?

• The reference of the array

• The copy of the array

• Length of the array

• Copy of first element

Arrays in java are

• Object references

• Objects

• Primitive

• None

Given that Student is a class, how many reference variables and objects are created by the following code?

1. Student studentName, studentId;  

2. studentName = new Student();  

3. Student stud_class = new Student();   

• 1. Three reference variables and two objects are created.

• 1. Two reference variables and two objects are created.

• 1. One reference variable and two objects are created.

• 1. Three reference variables and three objects are created.

When is the object created with new keyword?

• At run time

• At compile time

• Depends on the code

• None