What is the difference between String, StringBuffer and StringBuilder classes in Java explain briefly?

The String class of the java.lang package represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class. Strings are constant, their values cannot be changed after they are created.

The StringBuffer and StringBuilder classes are used when there is a necessity to make a lot of modifications to Strings of characters.

Unlike Strings, objects of type StringBuffer and String builder can be modified over and over again without leaving behind a lot of new unused objects.

The StringBuilder class was introduced as of Java 5 and the main difference between the StringBuffer and StringBuilder is that StringBuilder’s methods are not thread safe (not synchronized).

It is recommended to use StringBuilder whenever possible because it is faster than StringBuffer. However, if the thread safety is necessary, the best option is StringBuffer objects.

Example

 Live Demo

public class Sample {
   public static void main(String args[]){
      String str = new String("Hello how are you");
      StringBuffer sb = new StringBuffer(str);
      String str2 = sb.reverse().toString();
      System.out.println(str2);
   }
}

Output

uoy era woh olleH