Java String Coding Questions and Answers

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Welcome to the Java String Coding Quiz. In this quiz, we present 10 coding MCQ questions to test your coding knowledge on the Java String topic. Each question has a correct and brief explanation.

1. What is the output of the following Java code snippet?

String str = "Hello World";
System.out.println(str.length());

a) 10

b) 11

c) 12

d) 13

Answer:

b) 11

Explanation:

The length() method returns the number of characters in the string, including spaces. "Hello World" has 11 characters.

2. What does this Java code snippet output?

String s1 = "Java";
String s2 = new String("Java");
System.out.println(s1 == s2);

a) true

b) false

c) Java

d) An error

Answer:

b) false

Explanation:

'==' compares references, not values. s1 and s2 refer to different objects, so the output is false.

3. Identify the output of the following code:

String text = "JavaProgramming";
System.out.println(text.substring(4, 7));

a) Java

b) Prog

c) gram

d) Pro

Answer:

d) Pro

Explanation:

substring(int startIndex, int endIndex) returns the string from startIndex (inclusive) to endIndex (exclusive). Here, it's "Pro".

4. What will be printed by this Java code?

String str1 = "Java";
String str2 = "Java";
System.out.println(str1.equals(str2));

a) true

b) false

c) Java

d) An error

Answer:

a) true

Explanation:

The equals() method compares the values of strings. str1 and str2 have the same value, so the result is true.

5. What does this code snippet output?

String word = "Hello";
word.concat(" World");
System.out.println(word);

a) Hello

b) World

c) Hello World

d) An error

Answer:

a) Hello

Explanation:

Strings in Java are immutable. concat() creates a new string, which is not assigned to a word. So, the word remains unchanged.

6. What is the result of executing this code?

String a = "Java";
String b = " Programming";
String c = a + b;
System.out.println(c);

a) Java

b) Programming

c) Java Programming

d) An error

Answer:

c) Java Programming

Explanation:

The + operator concatenates two strings, creating a new string "Java Programming".

7. What will the following Java code snippet output?

String str = "Java";
System.out.println(str.toUpperCase());

a) java

b) JAVA

c) Java

d) An error

Answer:

b) JAVA

Explanation:

The toUpperCase() method converts all characters in the string to upper case.

8. What does the following code snippet print?

String text = "Java";
System.out.println(text.replace('a', 'x'));

a) Jxvx

b) Javx

c) Jxva

d) Java

Answer:

a) Jxvx

Explanation:

The replace(char oldChar, char newChar) method replaces all occurrences of the specified old character with the new character.

9. Determine the output of this Java code:

String s = "programming";
System.out.println(s.charAt(3));

a) p

b) r

c) o

d) g

Answer:

d) g

Explanation:

charAt(int index) returns the char value at the specified index. Indexing starts from 0, so s.charAt(3) is 'g'.

10. What is the result of the following code snippet?

String first = "Java";
String second = "Python";
System.out.println(first.compareTo(second));

a) A positive number

b) A negative number

c) 0

d) An error

Answer:

b) A negative number

Explanation:

compareTo() compares two strings lexicographically. Since "Java" is lexicographically less than "Python", it returns a negative number.

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