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Ans. java.lang.StringBuffer. | ||||
Sample Code for StringBuffer | ||||
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Like Discuss Correct / Improve  java   object class   stringbuffer expert   rare | ||||
Very frequently asked. Usually asked in different variants like Diff between StringBuffer , String Builder ; Difference between StringBuilder and String class; Choice between these classes etc. | ||||
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Ans. A string buffer implements a mutable sequence of characters. A string buffer is like a String, but can be modified. At any point in time it contains some particular sequence of characters, but the length and content of the sequence can be changed through certain method calls. The String class represents character strings. All string literals in Java programs, such as "abc" are constant and implemented as instances of this class; their values cannot be changed after they are created. | ||||
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Like Discuss Correct / Improve  java   string   stringbuffer   frequently asked Asked in 18 Companies basic   frequent | ||||
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Very Frequently asked. Usually asked along with String Class related questions. | ||||
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Ans. Class using which only immutable (objects that cannot be changed after initialization) objects can be created. | ||||
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Like Discuss Correct / Improve  java   oops   immutable  immutability   immutable  immutability class   string class   basic interview question Asked in 18 Companies Basic   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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This question was recently asked at 'Ariba'.This question is still unanswered. Can you please provide an answer. | ||||
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Like Discuss Correct / Improve  code  coding.string  trim a string Asked in 1 Companies | ||||
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Ans. JSON.stringify() turns an object into a JSON text and stores that JSON text in a string. So If we stringfy above notation , it will become {"name":"xyz","gender":"male";"age":30} | ||||
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Ans. private static boolean isPalindrome(String str) { if (str == null) return false; StringBuilder strBuilder = new StringBuilder(str); strBuilder.reverse(); return strBuilder.toString().equals(str); } | ||||
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Like Discuss Correct / Improve  java   string   stringbuilder   stringbuilder   string class   code   palindrome Asked in 38 Companies Basic   frequent | ||||
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Ans. private static String removeChar(String str, char c) { | ||||
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Ans. Since String is immutable, its hashcode is cached at the time of creation and it doesnt need to be calculated again. This makes it a great candidate for key in a Map and its processing is fast than other HashMap key objects. This is why String is mostly used Object as HashMap keys. | ||||
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Like Discuss Correct / Improve  java   string class   string   immutable  immutability   hashmap   immutable  immutability   hashcode   hash code   advanced Asked in 2 Companies expert   frequent | ||||
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Ans. intern() method keeps the string in an internal cache that is usually not garbage collected. Moreover provide reference for scp object for corresponding string object present in heap memory. | ||||
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Like Discuss Correct / Improve  java   string class   string   intern method   garbage collection   advanced Asked in 2 Companies expert | ||||
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Ans. substring method would build a new String object keeping a reference to the whole char array, to avoid copying it. Hence you can inadvertently keep a reference to a very big character array with just a one character string. | ||||
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Like Discuss Correct / Improve  java   string class   string   substring   memory leaks   jvm   memory management   advanced   architecture   technical architect   technical lead expert | ||||
Very frequently asked in HCL Tech ( Based of 4 inputs ) | ||||
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Ans. Using String method - new StringBuffer(str).reverse().toString(); Iterative - public static String getReverseString(String str){ StringBuffer strBuffer = new StringBuffer(str.length); for(int counter=str.length -1 ; counter>=0;counter--){ strBuffer.append(str.charAt(counter)); } return strBuffer; } Recursive - public static String getReverseString(String str){ if(str.length <= 1){ return str; } return (getReverseString(str.subString(1)) + str.charAt(0); } | ||||
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Like Discuss Correct / Improve  java   string   reverse   stringbuffer   string class   code Asked in 6 Companies   frequent | ||||
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Ans. public void checkIfAnagram(String str1,String str2){ boolean anagram = true; for(char c:str1.toCharArray()){ if(!str2.contains(String.valueOf(c))){ System.out.println("Strings are Anagrams"); anagram = false; } if(anagram == true){ System.out.println("Strings are not Anagrams"); } } } | ||||
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Like Discuss Correct / Improve   check if 2 strings are Anagrams Asked in 30 Companies basic   frequent | ||||
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Ans. true, due to String Pool, both will point to a same String object. | ||||
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Ans. Strings are immutable in Java and not final. | ||||
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Like Discuss Correct / Improve  is string final  final  string  immutable  immutability  immutability | ||||
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Ans. private void permutation(String prefix, String sufix) { int ln = sufix.length(); if(ln == 0) { System.out.println(prefix); } else { IntStream.range(0, ln).forEach(i->permutation(prefix sufix.charAt(i), sufix.substring(0,i) sufix.substring(i 1, ln))); } } call:permutation("", "abcdef"); | ||||
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Like Discuss Correct / Improve  String  code  coding Asked in 1 Companies | ||||
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Ans. public class BuggyBread1{ public static void main (String args[]) { String str = "hheello world"; char[] charArray = str.toCharArray(); char selectedChar = 'a'; for(char char1: charArray){ if(!str.contains(Character.toString(char1).concat(Character.toString(char1)))){ selectedChar = char1; break; } } System.out.println(str.indexOf(Character.toString(selectedChar))); } } | ||||
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Like Discuss Correct / Improve  string  code  coding Asked in 9 Companies | ||||
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Ans. toUpperCase and toLowerCase | ||||
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Like Discuss Correct / Improve  java   string class   string | ||||
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Ans. We can use String getBytes() method to convert String to byte array and we can use String constructor new String(byte[] arr) to convert byte array to String. | ||||
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Like Discuss Correct / Improve  java   string class   string | ||||
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Ans. S3 and S4 are pointing to different memory location and hence Output 1 will be false. Hash code is generated to be used as hash key in some of the collections in Java and is calculated using string characters and its length. As they both are same string literals, and hence their hashcode is same.Output 2 will be true. | ||||
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Ans. Hashcode is used for bucketing in Hash implementations like HashMap, HashTable, HashSet etc. | ||||
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Like Discuss Correct / Improve  java   string   hashcode   hash code   string comparison  hashtable Asked in 17 Companies basic   frequent | ||||
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Ans. equal 1 | ||||
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Ans. BuggyBread | ||||
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Ans. Buggy | ||||
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Ans. Buggy | ||||
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Ans. split() and macthes() | ||||
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Like Discuss Correct / Improve  java   io   string class   string   pattern | ||||
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Ans. 1 111 2 TreeSet maintains the elements in the ascending order which is identified by the compareTo method. compareTo method in String has been defined such that it results in the natural alphabetic Order. Here the elements in the TreeSet are of String and not of Integer. In String Natural Order, 111 comes before 2 as ascii of 1st character first determines the order. | ||||
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Ans. String str = new StringBuilder().append("Buggy").append("Bread").toString(); | ||||
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Ans. No, Alternatively I have used String.split("\\s") for achieving the same function. | ||||
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Like Discuss Correct / Improve  java   string   stringtokenizer | ||||
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Ans. http://www.buggybread.com/2015/01/java-string-classes-and-interfaces.html | ||||
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Like Discuss Correct / Improve  java   string | ||||