Java provides the StringBuffer and String classes. The String class is used to manipulate character strings that cannot be changed. To put it simply: objects of type String are read only and immutable.
The StringBuffer class is used to represent characters that cannot be modified.
The significant performance between these two classes is that the StringBuffer is remarkably faster than the String when performing simple concatenations.
Using the String class, we can concatenate as follows:
String str = new String("Lawson ");
str += "Luke";
With String Buffer …
StringBuffer strBuff = new StringBuffer("Lawson ");
strBuff.append("Luke");
To reverse a String …
public class StringReverse{
public static void main(String args[]){
String str = new String("Luke");
StringBuffer buff = new StringBuffer(str);
System.out.println(buff.reverse());
}
}