What we know about the "STRING"?

 

MCQ on String for concepts and interview preparation QAE - SDET - AUTOMATION QA 2022

1. What is the output for below?

String str1 = "test";
String str2 = "one";

String str3 = str1.concat(str2);

Ans:

a) testone

b) test

c) one

d) Let me check in IDE :)

2. What is the output for below?

String str1 = "test";
String str2 = "test";

String str3 = new String("test");

System.out.println(str1.equals(str2));

System.out.println(str1.equals(str3));

Ans:

a) true,true

b) false, true

c) false, false

d) Let me check in IDE :)

3. What is the output for below?

String str1 = "test";

String str2 = "test";

String str3 = new String("test");

System.out.println(str1==str2));

System.out.println(str1==str3);

a) true, true

b) true, false

c) false, true

d) false, false

4. What is the output for below?

String str = "test";

System.out.println(str1.charAt(2)); 

a) s

b) e

c) error

d) es

5. What is the output for below?

System.out.println("012301230123".replace(55, "45"));

 System.out.println("012301230123".replace("01", "45"));

a) compile error, 452345234523

b) 452345234523, 452345234523

c) error, error

d) Let me check in IDE :)

6. What is the output for below?

System.out.println("tes".substring(3));

System.out.println("test".substring(3));

a) error, error

b) error, t

c)  , t

d) t, t

7. How many ways we can create String Object in Java?

a) String s = "abc"; String s1 = new String("abc");

b) Literal, Keyword

c)  Both A and B

d)  Not sure

8. Is String thread safe?

a) true

b) false

c) Not sure

9. What is the output for below?

String str8 = new StringBuilder("test").reverse().toString();

System.out.println(str8);

a) test

b) tset

c) Not sure

10. Which one is thread safe: StringBuffer or StringBuffer ?

a) Both

b) StringBuffer

c) StringBuilder

d) None of the options

Below are the answers for all the questions on STRING:

1. a)testone

2. a)true,true

3. b)true, false

4. a)S

5. a) compile error, 452345234523

6. c)  , t

7. c)  Both A and B

8. a) true

9. b) tset