Core Java Interview Questions

How to reverse String in Java with or without using StringBuffer Example

<div dir&equals;"ltr" style&equals;"text-align&colon; justify&semi;">&NewLine;<div class&equals;"separator" style&equals;"clear&colon; both&semi; text-align&colon; center&semi;"><img title&equals;"How to reverse String in Java" src&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;wp-content&sol;uploads&sol;2017&sol;02&sol;How-to-Reverse-String-in-Java&period;jpg" border&equals;"0" &sol;><&sol;div>&NewLine;<p>How to reverse String in Java without StringBuffer is one of the popular core java interview question&period; If you are using StringBuffer or StringBuilder to reverse string then it is too easy because both classes have reverse&lpar;&rpar; method to achieving it&period; But if you are not using reverse&lpar;&rpar; method of these classes then it is some tricky question which requires you to reverse String by applying logic&period; You can reverse a string by two ways one you can use loop and another way you could use recursion because string reverse is a recursive job&period; Here in this java tutorial we are going to see how to reverse String using StringBuffer&comma; StringBuilder and using loop with logic&period; Let&&num;8217&semi;s see example&period;<&sol;p>&NewLine;<h2><b>Example of Reverse String in Java<&sol;b><&sol;h2>&NewLine;<p>Following program has complete code to reverse any String in Java&period; Here we have used StringBuffer and StringBuilder&&num;8217&semi;s reverse&lpar;&rpar; method first to reverse a String&period; Then we have used own logic to reverse String&period; In own logic we have used toCharArray&lpar;&rpar; method of String class which return character array of String as shown in following example&period;<&sol;p>&NewLine;<div style&equals;"background-color&colon; &num;f2f9fc&semi; border&colon;1px solid &num;c9e6f2&semi;border-radius&colon;3px&semi;padding&colon;16px&semi;line-height&colon;1&period;45&semi;">&NewLine;<span style&equals;"color&colon; red&semi;font-size&colon; x-large&semi;text-align&colon; center&semi;"><b>Popular Tutorials<&sol;b><&sol;span><&sol;p>&NewLine;<ul style&equals;"text-align&colon; 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&NewLine; &ast; &commat;author Dinesh&period;Rajput &NewLine; &ast; &NewLine; &ast;&sol; &NewLine;public class ReverseStringExample &lbrace; &NewLine; &NewLine; public static void main&lpar;String args&lbrack;&rsqb;&rpar; &lbrace; &NewLine; &NewLine; &sol;&sol;Reverse String in Java with Using StringBuffer &NewLine; String str &equals; "Dinesh on Java"&semi; &NewLine; String reverse &equals; new StringBuffer&lpar;str&rpar;&period;reverse&lpar;&rpar;&period;toString&lpar;&rpar;&semi; &NewLine; System&period;out&period;printf&lpar;" original String &colon; &percnt;s &comma; reversed String &percnt;s &percnt;n"&comma; str&comma; reverse&rpar;&semi; &NewLine; &NewLine; &sol;&sol;Reverse String in Java with Using StringBuilder &NewLine; str &equals; "Dinesh on Java"&semi; &NewLine; reverse &equals; new StringBuilder&lpar;str&rpar;&period;reverse&lpar;&rpar;&period;toString&lpar;&rpar;&semi; &NewLine; System&period;out&period;printf&lpar;" original String &colon; &percnt;s &comma; reversed String &percnt;s &percnt;n"&comma; str&comma; reverse&rpar;&semi; &NewLine; &NewLine; &sol;&sol;Reverse String in Java without Using StringBuffer or StringBuilder &NewLine; str &equals; "Dinesh on Java"&semi; &NewLine; reverse &equals; reverse&lpar;str&rpar;&semi; &NewLine; System&period;out&period;printf&lpar;" original String &colon; &percnt;s &comma; reversed String &percnt;s &percnt;n"&comma; str&comma; reverse&rpar;&semi; &NewLine; &rcub; &NewLine; &NewLine; &NewLine; public static String reverse&lpar;String source&rpar;&lbrace; &NewLine; if&lpar;source &equals;&equals; null &vert;&vert; source&period;isEmpty&lpar;&rpar;&rpar;&lbrace; &NewLine; return source&semi; &NewLine; &rcub; &NewLine; String reverse &equals; ""&semi; &NewLine; for&lpar;int i &equals; source&period;length&lpar;&rpar; -1&semi; i&gt&semi;&equals;0&semi; i--&rpar;&lbrace; &NewLine; reverse &equals; reverse &plus; source&period;charAt&lpar;i&rpar;&semi; &NewLine; &rcub; &NewLine; &NewLine; return reverse&semi; &NewLine; &rcub; &NewLine; &NewLine;&rcub; &NewLine;<&sol;pre>&NewLine;<p><b>Output<&sol;b><br &sol;>&NewLine;<i>original String &colon; Dinesh on Java &comma; reversed String avaJ no hseniD <&sol;i><br &sol;>&NewLine;<i>original String &colon; Dinesh on Java &comma; reversed String avaJ no hseniD <&sol;i><br &sol;>&NewLine;<i>original String &colon; Dinesh on Java &comma; reversed String avaJ no hseniD <&sol;i><&sol;p>&NewLine;<p>Above example shown many ways to reverse a String in java but as java programmer always use StringBuffer or StringBuilder method to reverse String for real project&period;<&sol;p>&NewLine;<div style&equals;"background-color&colon; &num;f2f9fc&semi; border-radius&colon; 3px&semi; border&colon; 1px solid &num;c9e6f2&semi; line-height&colon; 1&period;45&semi; padding&colon; 16px&semi;">&NewLine;<p><b>String Related Posts<&sol;b><&sol;p>&NewLine;<ol style&equals;"text-align&colon; left&semi;">&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2014&sol;11&sol;how-to-make-java-class-immutable&period;html">How to make Immutable Class in Java<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;core-java-interview-questions&period;html">Core Java Interview Questions<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2013&sol;02&sol;string-class-in-java&period;html">String Class in Java<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;why-string-is-immutable-and-final-in-java&period;html">Why String is Immutable and Final in Java<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;convert-string-to-integer-to-string-in-java-with-example&period;html">Convert String to Integer to String in Java with Example<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;convert-double-to-string-to-double-in-java-with-example&period;html">Convert Double to String to Double in Java with Example<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;convert-date-to-string-in-java-with-example&period;html">Convert Date to String in Java with Example<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;simpledateformat-in-java-format-date-to-string-to-date-with-example&period;html">SimpleDateFormat in Java- format Date to String to Date with Example<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;differences-between-string-stringbuffer-and-stringbuilder-in-java&period;html">Differences between String&comma; StringBuffer and StringBuilder in Java<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;difference-between-stringbuilder-and-stringbuffer-in-java&period;html">Differences StringBuffer and StringBuilder<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;how-to-compare-two-strings-in-java&period;html">How to Compare two Strings in Java<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2017&sol;02&sol;hashcode-and-equals-methods-in-java&period;html">Difference between hashCode&lpar;&rpar; and equals&lpar;&rpar; methods in Java<br &sol;>&NewLine;<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2013&sol;03&sol;java-string-substring-method&period;html"> Java &&num;8211&semi; String substring&lpar;&rpar; Method<br &sol;>&NewLine;<&sol;a><&sol;b><&sol;li>&NewLine;<li><b><a href&equals;"https&colon;&sol;&sol;dineshonjava&period;com&sol;2013&sol;05&sol;difference-between-wait-and-sleep&period;html"> Difference between wait&lpar;&rpar; 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Dinesh Rajput

Dinesh Rajput is the chief editor of a website Dineshonjava, a technical blog dedicated to the Spring and Java technologies. It has a series of articles related to Java technologies. Dinesh has been a Spring enthusiast since 2008 and is a Pivotal Certified Spring Professional, an author of a book Spring 5 Design Pattern, and a blogger. He has more than 10 years of experience with different aspects of Spring and Java design and development. His core expertise lies in the latest version of Spring Framework, Spring Boot, Spring Security, creating REST APIs, Microservice Architecture, Reactive Pattern, Spring AOP, Design Patterns, Struts, Hibernate, Web Services, Spring Batch, Cassandra, MongoDB, and Web Application Design and Architecture. He is currently working as a technology manager at a leading product and web development company. He worked as a developer and tech lead at the Bennett, Coleman & Co. Ltd and was the first developer in his previous company, Paytm. Dinesh is passionate about the latest Java technologies and loves to write technical blogs related to it. He is a very active member of the Java and Spring community on different forums. When it comes to the Spring Framework and Java, Dinesh tops the list!

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