PU - Day 1 assessment - Kalpana's batch

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

• A

• B

• C

• D

Which of the following statements about StringBuffer is true?
a) StringBuffer is immutable
b) StringBuffer is synchronized
c) StringBuffer cannot be converted to a String
d) StringBuffer is a subclass of String

• A

• B

• C

• D

What will be the output of the following code snippet?
String str = "Hello";
str.concat(" World");
System.out.println(str);
a) Hello World
b) Hello
c) Compilation error
d) Runtime error

• D

• B

• C

• A

Which of the following methods can be used to compare two strings in Java?
a) compareTo()
b) equalsIgnoreCase()
c) both a and b
d) none of the above

• C

• B

• A

• D

What will be the output of the following Java program?

1. class string_class

2. {

3. public static void main(String args[])

4. {

5. String obj = "I LIKE JAVA";

6. System.out.println(obj.charAt(3));

7. }

8. }

• K
• L
• I
• A

What will be the output of the following code snippet?
String str = "Java";
str = str + " Programming";
System.out.println(str);
a) Java Programming
b) Java
c) Compilation error
d) Runtime error

• B

• A

• C

• D

Which of the following statements about StringBuilder is true?
a) StringBuilder is synchronized
b) StringBuilder is mutable
c) StringBuilder cannot be converted to a String
d) StringBuilder is a subclass of String

• D

• C

• B

• A

Which of the following methods can be used to find the length of a String in Java?
a) length()
b) size()
c) getLength()
d) count()

• D

• B

• C

• A

Which of the following statements about String immutability is true?
a) Strings can be changed after creation
b) Strings are stored in a mutable way
c) Strings cannot be altered once created
d) Strings are synchronized

• C

• A

• B

• D

What will be the output of the following code snippet?
String str = "Hello";
str = str.replace('e', 'a');
System.out.println(str);
a) Hello
b) Hallo
c) Halla
d) Compilation error

• D

• C

• B

• A