[Solved] How to count Vowels and Consonants in Java String Word? Example

Hello guys, if you are wondering how to count number of vowels and consonants in a given word in Java then you have come to the right place. In the past, I have shared 100+ data structure questions and more than 75 programming interview questions, and In this article, we will take on a popular programming exercise of counting vowels in a word. You need to write a Java program to count how many vowels in a String, which is entered from the command prompt. It's similar to the program of counting the occurrence of characters in a String, in fact, it's a special case, where you need to count occurrences of all vowels, which includes five characters a, e, i, o and u. 

[Solved] How to Check If a Given String has No Duplicate Characters in Java? Unique Example

Hello guys, if you are looking to solve the classic problem "checking if a String has all Unique characters" or not then you have come to the right place. Earlier, I have shown you how to reverse String in place, and in this article, I will show you how to check for unique and duplicate characters in String.  You need to write a program to determine if a given string has all unique characters or not. For example input= "Java" then your function should return false because all characters are not unique, and if the input is "Python" then your program should return true because all characters in Python are unique.

[Solved] How to reverse a String in place in Java? Example

One of the common Java coding interview questions is to write a program to reverse a String in place in Java, without using additional memory. You cannot use any library classes or methods like StringBuilder to solve this problem. This restriction is placed because StringBuilder and StringBuffer class define a reverse() method which can easily reverse the given String. Since the main objective of this question is to test the programming skill and coding logic of the candidate, there is no point in giving him the option to use the library method which can make this question trivial. 

How to remove duplicate characters from String in Java? [Solved]

Hello all, how are you doing? It's been a long since I have shared a coding problem from the interview. The last one I discussed was about finding the Nth Fibonacci number, one of the popular dynamic programming problems. Never mind,  today, you are going to learn about another popular coding problem.  How do you remove duplicate or repeated characters from String in Java is one of the frequently asked string-based coding problems from Interviews. This problem is very similar to removing duplicate elements from an array which we have discussed in the past here after all String is a character array in Java. If you know how to solve that problem, you should be able to solve this one as well.

[Solved] How to find the Longest common prefix in Array of String in Java? Example Tutorial

Hello guys, If you are preparing for technical interviews and wondering how to solve the longest common prefix in a given array of String problems in Java then you have come to the right place. Earlier, I have shared 21 String programming problems and one of them was this one. In this article, I am going to show you how to solve this frequently asked coding problem from Java Interviews. It's one of the difficult coding problems and not every programmer I have interviewed has solved this, only a few can solve this so preparing for this one can definitely improve your chances and give you a competitive edge over other candidates.

[Solved] How to check if two String are Anagram in Java? Example

Hello guys, if you are preparing for Coding interviews then you already know that String is one of the most popular topics. You will be bound to get some string-based coding problems on interviews. If not, you have come to the right place becuase we'll look at one of the most popular String programming interview questions today,  how to check if two given strings are Anagram of each other? Two String is said to be an anagram of each other, if they contain exactly the same characters but in a different order. For example "ARMY" and "MARY" are an anagram of each other because they contain the exact same characters 'A', 'R', 'M' and  'Y'.

[Solved] How to Find Repeated Characters in a given String with count in Java? Example

This is another interesting coding problem or programming exercise for beginner programmers. How do you find repeated or duplicate characters in a given String and their count? You can solve this coding problem in any programming language of your choice like Java, Python, Ruby, or even JavaScript. I'll explain the logic and solution which is easy to implement in the above programming languages and I'll provide code in Java, which is my favorite programming language.  In order to solve this problem, You need to first check if a String contains any duplicate characters or not, and then if it contains any duplicate letters then find out how many times they appear in the given input String.

Top 35 Java String Interview Questions with Answers for 2 to 5 Years Experienced Programmers

Hello Java Programmers, if you are preparing for a Java developer interview and want to refresh your knowledge about  String class in Java then you have come to the right place. In the past, I have shared 130+ Core Java Interview Questions and 21 String Coding Problems for Interviews and in this article, I am going to share 35 Java String Questions for Interviews. The  String class and concept is a very important class in Java. There is not a single Java program out there which is not use String objects and that's why it's very important from the interview point of view as well. In this article, I am going to share 35 String-based questions from different Java interviews.

Difference between StringBuilder and StringBuffer in Java with Example

If you are in a hurry and heading straight to interview then I won't take much of your time, In a couple of words, the main difference between StringBuffer and StringBuilder is between four parameters, synchronization, speed, thread-safety, and availability. StringBuffer is synchronized and that's why thread-safe, but StringBuilder is not synchronized, not thread-safe and that's why fast. Regarding availability, StringBuffer is available from Java 1.0 while StringBuilder was added in Java 5. 

How to check if strings are rotations of each other in Java? String Rotation Example Solution

String-based algorithmic questions are very popular in Java interviews e.g. checking if two String is the anagram of each other (see), or checking if given String is a palindrome (see), or just finding permutations of given String (see). One of such popular String-based interview questions is about to check if two Strings are a rotation of each other in Java. In order to solve this question, you should know what is String rotation? Well, A string is made of characters and you just rotate the String around any character like "programming" will become "ingprogramm" if we rotate the String on the trailing character 3 times.

How to Reverse words in String Java? [Solution]

Hello guys, if you are wondering how to reverse words in a given String in Java then you have come to the right place. Earlier, I have shared 75 Programming interview questions and In this Java Coding tutorial, you will learn how to reverse words in String. It's also one of the popular coding questions, so you will also learn how to take a requirement, how to fill gaps in the requirement by asking the right question. A String is nothing but a sentence, which may contain multiple works, or just contain a single word or it may be empty. Your program must produce a String that contains the word in reverse order, for example, if the given input is "Java is Great" then your program should return "Great is Java".  

How to check is given String is a Palindrome in Java using Recursion

In this tutorial, you will learn how to check if a string is a palindrome in Java using Recursion. A String is nothing but a collection of characters like "Java," and String literals are encoded in double-quotes in Java. A String is said to be a palindrome if the reverse of String is equal to itself like "aba" is a palindrome because the opposite of "aba" is also "aba", but "abc" is not a palindrome because the reverse of "abc" is "cba" which is not equal. Recursion means solving a problem by writing a function which calls itself. In order to check if String is a palindrome in Java, we need a function that can reverse the String.

How to Reverse String in Java with or without StringBuffer Example

Reverse String in Java

There are many ways to reverse a given String in Java. For example, you can use rich Java API to quickly reverse the contents of any String object. Java library provides StringBuffer and StringBuilder class with the reverse() method which can be used to reverse String in Java. Since converting between String and StringBuffer or StringBuilder is very easy it's the easiest way available to reverse String in Java. But, in a coding interview, you may not be allowed to use the JDK API methods to solve this problem. That's why, writing a Java program to reverse String in Java without StringBuffer is one of the popular Java String interview questions, which requires you to reverse String by applying logic and by not using API methods.

How to Remove all adjacent duplicates characters from String in java? Example Tutorial

Hello guys, if you are wondering how to remove adjacent repeated characters or duplicates from a given String in Java then you have come to the right place. In the last article, we have seen how to find duplicate characters as well as how to remove duplicate characters from String in Java, and in this article, we will take that topic to another level and remove adjacent duplicates from given String. This topic gives another perspective to removing duplicates in a word or phrase. Probably before now, you are familiar with removing duplicates from a word or phrase, or number. But this topic gives a detailed understanding of how to remove adjacent duplicates. 

How to count a number of words in given String in Java? [Solved]

Can you write a method in Java that accepts a String argument and returns a number of words in it? A word is a sequence of one or more non-space characters i.e. any character other than '' (empty String). This should be your method signature:

public int count(String word);

This method should return 1 if the input is "Java" and return 3 if the input is "Java, C++, Python". Similarly a call to wordCount("    ") should return 0. 

3 ways to Count words in Java String - Google Interview Questions with Solution

Today, I am going to share with you Java interview questions from Google, which were asked to one of my readers during the telephonic round. How do you count the number of words in a given String in Java? You can count words in Java String by using the split() method of String. A word is nothing but a non-space character in String, which is separated by one or multiple spaces. By using a regular expression to find spaces and split on them will give you an array of all words in a given String. This was the easy way to solve this problem as shown here, but if you have been asked to write a program to count a number of words in a given String in Java without using any of String utility methods like String.split() or StringTokenizer then it's a little bit challenging for a beginner programmer.

3 ways to check if a String contains SubString in Java? IndexOf, contains, and lastIndexOf Example

You have given a String and a subString or a character and you need to find out whether given String contains the given character or substring, how would you do that? Well, there are three main ways to search String in Java, the contains() method, the indexOf() method and the lastIndexOf() method, all from java.lang.String class. First method, contains() accepts a CharSequence, superclass of String and return true if that CharSequence appear on the String you have called. The indexOf() and lastIndexOf() are similar method and both return the index (zero based) from where the given subString or character appear in the String you have called. Only difference between indexOf() and lastIndexOf() is that if given substring appear multiple time then they will return difference index, otherwise both will return the same index. Similarly if given sub-string is not present in the String, both will return -1 and contains() will return false.

Top 21 String Programming and Coding Interview Questions With Solutions

In this article, I am going to share 21 of the most common String-based Programming and Coding interview questions from Java developer interviews. These questions require you to write code to solve the problem and they are different from traditional Java String questions like how the substring method works in Java? or when to use the intern() method of String in Java? Since coding and problem solving are an important part of any programming job interview, it's imperative that you know how to solve them in time and in a pressure situation, which comes only after doing practice with the right set of questions. Since these questions are already tried and tested and appeared in many interviews, they will provide you the experience you need to crack your coding interview.

How to remove given character from String using Recursion and Iteration in Java? Coding Interview Question

Hello guys, in the past, I have discussed several popular and frequently asked Java programs from interviews and coding interview questions and today, I am going to share another popular String based coding interview question for Java developers. The questions goes as - write a method to remove all occurence of a given character from String in Java, you can not use a library method like replace() or remove() which can solve the problem for you. You have to build the logic by yourself. You have to provide both iterative and recursive solution of this question. Along with that, you have to provide some unit test as well, which you can write using JUnit or TestNG testing framework. 

Right way to check if String is empty in Java with Example

What do most of us Java Programmers do while using String in Java? Check whether String is null or empty right? I am sure you know a couple of ways to test whether String is empty or not, but do you know the right way to do it? When we talk about Strings in Java, we can imagine them as arrays of characters, and they are, but in Java, they also object. An empty Java String is considered as the not null String that contains zero characters, meaning its length is 0. However, a Java String that might only contain the white-space character is not considered empty, it is considered to contain one character and its length is equal to 1.