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| Core java - Interview Questions and Answers for 'Jpmorgan chase' - 5 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) | ||||
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| 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 | ||||
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 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 | ||||
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| Very frequently asked across all types of companies. | ||||
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| Ans. Hashtable is synchronized whereas HashMap is not.HashMap allows null values whereas Hashtable doesnt allow null values. | ||||
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| Discuss Correct / Improve java collections hashmap map hashtable hashmap vs hashtable Asked in 14 Companies basic frequent | ||||
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| Ans. We can make a class immutable by 1. Making all methods and variables as private. 2. Setting variables within constructor. Public Class ImmutableClass{ private int member; ImmutableClass(int var){ member=var; } } and then we can initialize the object of the class as ImmutableClass immutableObject = new ImmutableClass(5); Now all members being private , you cant change the state of the object. | ||||
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| Discuss Correct / Improve java oops immutable immutability immutable immutability class technical lead Asked in 5 Companies intermediate frequent | ||||
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| Very frequently asked in phone and walk in interviews. | ||||
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| Ans. An interface without any method declaration is called as marker interface. there are 3 in-built interfaces in JVM i.e. serializable, clonable, remote | ||||
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| Discuss Correct / Improve java oops interfaces marker interface serializable clonable Asked in 21 Companies intermediate frequent | ||||
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| Very frequently asked. Usually difference between String,StringBuffer and StringBuilder is asked in different variations. | ||||
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| Ans. StringBuffer is synchronized whereas StringBuilder is not. | ||||
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| Discuss Correct / Improve java string stringbuffer string class stringbuilder synchronized basic interview question infosys technologies Asked in 17 Companies basic frequent | ||||
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Which of the following has been introduced with Java 8 ?
