Difference Between String and StringBuffer Class in Java

In this post, we will understand the difference between String and StringBuffer class in Java.

String

• It is an immutable class.

• This means changes can’t be made to elements of the class.

• It is slow.

• It consumes less memory when strings are concatenated.

• This is because every time, a new instance is created.

• It overrides the equals() method of Object class.

• Hence, the ‘equals’ method can be used to compare two strings.

Following is an example of the String class −

Example

public class StringDemo {
   public static void main(String args[]) {
      String palindrome = "Dot saw I was Tod";
      int len = palindrome.length();
      System.out.println( "String Length is : " + len );
   }
}

StringBuffer

• It is a mutable class.

• This means changes can be made to the elements in this class.

• It is fast.

• It uses less memory when strings are concatenated.

• It class doesn't override the equals() method of Object class.

Following is an example of the StringBuffer class −

Example

public class Demo {
   public static void main(String args[]) {
      StringBuffer sBuffer = new StringBuffer("test");
      sBuffer.append(" String Buffer");
      System.out.println(sBuffer);
   }
}