StringBuffer and StringBuilder

Last Updated on March 14, 2023 by Prepbytes

Strings in Java are immutable, which means that we cannot change the value of a String object. Even, if we try to change the value of a String object, Java will create a new String object with the modified value in heap memory. Both String Buffer and String Builder classes in Java provide us with the functionality of mutable Strings. While moving further down in this article, we will look at what is String Buffer and String Builder and we’ll also compare String Buffer and String Builder classes in Java.

What is StringBuffer in Java?

String Buffer in Java provides a straightforward and efficient way to manage strings and is generally used in many applications for string-related operations. String Buffer class in Java provides a number of methods for performing operations such as concatenating two strings, adding characters in a string, and removing characters from a string. The String Buffer class is similar to the String class in Java, but it differs in the aspect that String Buffer objects can be modified, whereas String objects are immutable (i.e., meaning that once created they cannot be changed later on).

To learn and explore more about StringBuffer in Java, please go to this page.

What is StringBuilder in Java?

The String Builder class in Java is very similar to the String Buffer class, with only a few differences. One of the differences is that the String Builder class is not thread-safe and because of this, its methods are found to be faster compared to the String Buffer methods. The String Builder class does not ensure synchronization, while the String Buffer class methods are synchronized. However, when most of the string operations are executed on the same thread, the String Builder class is preferred over the String Buffer class.

Syntax of StringBuilder Class in Java
The basic syntax for using the String Builder class in Java is

StringBuilder sb = new StringBuilder("PrepBytes");

Let’s take an example to understand how to use the String Builder class in Java

import java.util.*;
import java.lang.*;
import java.io.*;

class StringBuilderExample {

  public static void main(String[] args) {
    StringBuilder sb = new StringBuilder("PrepBytes");
    System.out.println(sb);
    // Updating/Modifying the StringBuilder object value
    sb.append(" Articles");
    System.out.println(sb);
  }
}

Output:

PrepBytes
PrepBytes Articles

Explanation: In the above example, we first create a String Builder object of “PrepBytes” and later on we try to append “articles” in our String Builder object to demonstrate its mutable string functionality.

StringBuilder Vs StringBuffer

There are some differences between String Buffer and String Builder class in Java and an overview of those differences is provided in the below StringBuilder Vs StringBuffer table.

Summary

• Strings in Java are immutable. To construct and manipulate mutable Strings, Java provides the String Buffer and String Builder classes.
• String Buffer is a thread-safe class which means that several threads operating on shared data are synchronized.
• The String Builder class is not thread-safe which implies that operations of many threads on shared data are not synchronized.
• Because of the additional checks required for thread safety, String Buffer class operations are generally slower when compared to String Builder class operations.

FAQ Related to StringBuffer and StringBuilder

Here are some frequently asked questions on String Buffer and String Builder classes in Java

Q1: When should I prefer using string buffer over string builder in Java?
A: You can use string buffer over string builder when you need to manipulate strings in a multi-threaded environment, as string buffer is thread-safe than string builder.

Q2: When should I prefer using string builder over string buffer in Java?
A: You can use string builder over string buffer when you need to manipulate strings in a single-threaded environment, as string builder is faster than string buffer.

Q3: What methods are available in string buffer and string builder classes in Java?
A: String buffer and string builder classes in Java provide methods like append, insert, and delete characters from a string. They also provide other methods like reverse a string, get the length of a string and get a substring.

Q4: Can I use a string buffer or string builder to concatenate strings in Java?
A: Yes, you can use string buffer or string builder to concatenate strings in Java.