Difference Between StringBuffer and StringBuilder class

In this article, we are going to discuss the differences between the StringBuffer and StringBuilder class. And we will see why it StringBuilder is preferable to StringBuffer class.”

Introduction

The String class is one of the most important classes in Java. In every day to day coding in Java, we use string many times.

We create a new string and perform various operations on it, like adding a character or removing a character, but do you know every time you operate on the string, each time a new string object is created and assigned to your current string variable.

Yes, it happens under the hood.

Most of us know that String is immutable. This means we can not edit the current string object, when we try to do it we are creating a new string object.

As I said in the very first line, String is one of the most important classes in Java and we use it many times in our code. The number of operations creates the same amount of garbage string objects, which put pressure on the Garbage Collector.

Taking this need into consideration the Java Team introduce StringBuffer class.

StringBuffer is mutable. You can edit it. But we can say that the Java Team was more concern about the correctness of the operations so they made it synchronized. All methods of the StringBuffer class are synchronized.

But what does it mean by the word ‘synchronized’?

Synchronization is the capability to control the access of methods. An only a single thread can access a method at one time.

That means all the methods of the StringBuffer class can be accessed by a single thread at a time.

After using it for a while, java developers feel that the StringBuffer is taking more time because of synchronization. Making all methods of StringBuffer class synchronized is not required. Then the Java team realize making StringBuffer class synchronized wasn’t a great decision and they corrected it by introducing the StringBuilder class in Java 1.5.

StringBuilder class is like StringBuffer only but with one difference.

StringBuffer is synchronized, StringBuilder is not.

Now we will discuss the difference between the StringBuffer and StringBuilder class in detail.

Difference Between StringBuffer and StringBuilder

To understand the difference between the StringBuffer and StringBuilder class we should first understand the need for the StringBuilder class.

We have discussed earlier that because of day to day use and a lot of pressure on the Garbage collector due to garbage string objects, the java team introduced StringBuffer class. They made it synchronized in concern with the correctness.

Making StringBuffer class synchronized causing the performance issue and that’s why StringBuilder came.

Now you can learn the difference, the StringBuffer class is synchronized while the StringBuilder class is not.

But this is the main difference. We will discuss a few more differences which came into the existence because of this main difference.

In support of the above discussion, we will see the first paragraph from the Java API documentation of the StringBuilder class, that states you should give preference to the StringBuilder class.

A mutable sequence of characters. This class provides an API compatible with StringBuffer, but with no guarantee of synchronization. This class is designed for use as a drop-in replacement for StringBuffer in places where the string buffer was being used by a single thread (as is generally the case). Where possible, it is recommended that this class be used in preference to StringBuffer as it will be faster under most implementations.

Also, I will like to share one detail with you, when you perform the string concatenation operation and if you are using Java 1.4 or lower then java internally using StringBuffer class for string concatenation operation.

After an introduction to StringBuilder class in Java 1.5, from Java 1.5 and higher Java internally uses StringBuilder class for string concatenation.

Conclusion

The most important difference between the StringBuffer class and StringBuilder class is

StringBuffer is synchronized, StringBuilder is not.

So, StringBuffer class takes more time as compare to StringBuilder class for performing the same operation.

Taking efficiency into consideration, it is highly recommended to use StringBuilder class instead of the old StringBuffer class.

Also, if you have other information about the difference between StringBuffer class and StringBuilder class please write it down in the comment section below.