Core Java - Interview Questions and Answers for 'Stringbuilder' - 6 question(s) found - Order By Newest Very frequently asked in different variations. Frequently asked in Deloitte ( 2 feedback ) , HCL Tech ( 3 feedback ), TCS and Coginizant (CTS) Q1. Explain the scenerios to choose between String , StringBuilder and StringBuffer ?
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What is the difference between String , StringBuilder and StringBuffer ? Core Java
Ans. If the Object value will not change, use String Class because a String object is immutable.
If the Object value can change and will only be modified from a single thread, use StringBuilder because StringBuilder is unsynchronized(means faster).
If the Object value may change, and can be modified by multiple threads, use a StringBuffer because StringBuffer is thread safe(synchronized). Sample Code for String Sample Code for StringBuffer Sample Code for StringBuilder Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  java   string class   string   stringbuilder   stringbuffer   String vs StringBuffer   String vs StringBuilder   String vs StringBuilder vs StringBuffer   StringBuffer vs stringBuilder Asked in 29 Companies basic   frequent Try 3 Question(s) TestVery frequently asked. Usually difference between String,StringBuffer and StringBuilder is asked in different variations. Q2. Difference between StringBuffer and StringBuilder ? Core Java
Ans. StringBuffer is synchronized whereas StringBuilder is not. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  java   string   stringbuffer   string class   stringbuilder   synchronized   basic interview question   infosys technologies Asked in 17 Companies basic   frequent Try 1 Question(s) Test Q3. Write a method to check if input String is Palindrome? Core Java
Ans. private static boolean isPalindrome(String str) {
if (str == null)
return false;
StringBuilder strBuilder = new StringBuilder(str);
strBuilder.reverse();
return strBuilder.toString().equals(str);
} Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  java   string   stringbuilder   stringbuilder   string class   code   palindrome Asked in 38 Companies Basic   frequent Q4. Give an Example for Builder Pattern ? Core Java
Ans. String str = new StringBuilder().append("Buggy").append("Bread").toString(); Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  java   builder pattern   design pattern   stringbuilder   string Asked in 3 Companies Try 1 Question(s) Test Q5. Can StringBuffer and StringBuilder in Java be inherited? Core Java
Ans. No, they have been declared final and hence cannot be extended. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  StringBuffer  StringBuilder Q6. Do we have a method to reverse a string in String class ? Core Java
Ans. No but we have it in StringBuilder. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  String  StringBuilder  Reverse a string a. String b. StringBuffer c. StringBuilder d. None of these create immutable objects.Ans.a. String
a. String b. StringBuffer c. StringBuilder d. None of theseAns.b. StringBuffer
Q9. Which of the following class cannot be extended or inherited ?
StringBuffer , StringBuilder Core Java
a. StringBuffer b. StringBuilder c. Both cannot be extended d. Both can be extendedAns.c. Both cannot be extended