Java Questions & Answers – String Class

This section of our 1000+ Java MCQs focuses on String class of Java Programming Language.

1. String in Java is a?
a) class
b) object
c) variable
d) character array
View Answer

Answer: a
Explanation: None.

2. Which of these method of String class is used to obtain character at specified index?
a) char()
b) Charat()
c) charat()
d) charAt()
View Answer

Answer: d
Explanation: None.

3. Which of these keywords is used to refer to member of base class from a sub class?
a) upper
b) super
c) this
d) None of the mentioned
View Answer

Answer: b
Explanation: Whenever a subclass needs to refer to its immediate superclass, it can do so by use of the keyword super.

4. Which of these method of String class can be used to test to strings for equality?
a) isequal()
b) isequals()
c) equal()
d) equals()
View Answer

Answer: d
Explanation: None.

5. Which of the following statements are incorrect?
a) String is a class.
b) Strings in java are mutable.
c) Every string is an object of class String.
d) Java defines a peer class of String, called StringBuffer, which allows string to be altered.
View Answer

Answer: b
Explanation: Strings in Java are immutable that is they can not be modified.

6. What is the output of this program?

  1.     class string_demo {
  2.         public static void main(String args[])
  3.         {
  4.             String obj = "I" + "like" + "Java";   
  5.             System.out.println(obj);     
  6.         }
  7.    }

a) I
b) like
c) Java
d) IlikeJava
View Answer

Answer: d
Explanation: Java defines an operator +, it is used to concatenate strings.
output:
$ javac string_demo.java
$ java string_demo
IlikeJava

7. What is the output of this program?

  1.     class string_class {
  2.         public static void main(String args[])
  3.         {
  4.             String obj = "I LIKE JAVA";   
  5.             System.out.println(obj.charAt(3));
  6.         } 
  7.     }

a) I
b) L
c) K
d) E
View Answer

Answer: a
Explanation: charAt() is a method of class String which gives the character specified by the index. obj.charAt(3) gives 4th character i:e I.
output:
$ javac string_class.java
$ java string_class
I

8. What is the output of this program?

  1.     class string_class {
  2.         public static void main(String args[])
  3.         {
  4.             String obj = "I LIKE JAVA";   
  5.             System.out.println(obj.length());
  6.         }
  7.     }

a) 9
b) 10
c) 11
d) 12
View Answer

Answer: c
Explanation: None.
output:
$ javac string_class.java
$ java string_class
11

9. What is the output of this program?

  1.     class string_class {
  2.         public static void main(String args[])
  3.         {
  4.             String obj = "hello";
  5.             String obj1 = "world";   
  6.             String obj2 = obj;
  7.             obj2 = " world";
  8.             System.out.println(obj + " " + obj2);
  9.         }
  10.     }

a) hello hello
b) world world
c) hello world
d) world hello
View Answer

Answer: c
Explanation: None.
output:
$ javac string_class.java
$ java string_class
hello world

10. What is the output of this program?

  1.     class string_class {
  2.         public static void main(String args[])
  3.         {
  4.             String obj = "hello";
  5.             String obj1 = "world";   
  6.             String obj2 = "hello";
  7.             System.out.println(obj.equals(obj1) + " " + obj.equals(obj2));
  8.         }
  9.     }

a) false false
b) true true
c) true false
d) false true
View Answer

Answer: d
Explanation: equals() is method of class String, it is used to check equality of two String objects, if they are equal, true is retuned else false.
output:
$ javac string_class.java
$ java string_class
false true

Sanfoundry Global Education & Learning Series – Java Programming Language.

About

Manish Bhojasia, a technology veteran with 17+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer and SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage & Cluster Administration, Advanced C Programming, SAN Storage Technologies, SCSI Internals and Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him below.


Sanfoundry Training Center of Excellence (CoE)

Manish Bhojasia, a technology veteran with 17+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer and SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage & Cluster Administration, Advanced C Programming, SAN Storage Technologies, SCSI Internals and Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him below.







Subscribe Newsletter & Posts
Sanfoundry Internships
Follow Manish & Sanfoundry