3 ways to Reversing String In JAVA

This is the most asked question in Java programming interviews, and there are many ways to do it

Using Java’s String Buffer’s reverse method:

String str = "Reverse This String";
StringBuffer str1 = new StringBuffer(str);
System. out.println("Reversed String : "+str1.reverse());

Although we can use inbuilt Java methods to reverse the string, it is good to know alternatives of it, so let’s check other ways to reverse a string without using inbuilt functions

2. Reverse String using for loop and character array

This is the traditional way of reversing a string in which we traverse through the array backwards.

String str = "Reverse This String";

char [] strCharArray = str.toCharArray() ;
StringBuffer revr = new StringBuffer();
for(int i=strCharArray.length-1;i>-1;i--){
    revr.append(strCharArray[i]);
}
System.out.println("Reversed String : "+revr);

3. Reverse String using reduce function

String str = "Reverse This String";

String reveresed = str.chars().mapToObj(
        c -> (char)c).
        reduce("",(sa,c)->c+sa,(s1,s2)->s2+s1);
System.out.println("Reversed String :"+reveresed);

It’s also common in interviews that they ask to reverse a sentence without disturbing its sequence.

For example Input — Reverse this string. Output — esreveR sihT gnirtS

String str = "Reverse This String";
String words[] = str.split(" ");
StringBuffer strReversed = new StringBuffer();

for(int i=0;i< words.length;i++){
        for(int j=words[i].length()-1;j>-1;j--){
            char [] wordsCharArray = words[i].toCharArray();
            strReversed.append(wordsCharArray[j]);
    }
    strReversed.append(" ");
    }
System.out.print(strReversed);

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