In this shot, we will discuss the difference between the `String` and `StringBuffer` classes in Java.

The table below lists some of the differences in properties between `String` and `StringBuffer`.


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## Code

In the code below, we create objects of both the `String` and `StringBuffer` classes.

We perform concatenation on `String` instances with the `+=` operator and concatenation on `StringBuffer` instances with the `append()` method.

class Main
{
    public static void main(String[] args) 
    {

        String s = new String("This ");
        s += "is a ";
        s += "String object";
        System.out.println(s);

        StringBuffer sb = new StringBuffer("This ");
        sb.append("is a ");
        sb.append("StringBuffer object");
        System.out.println(sb);
    }
}


#    
## Explanation

* In line 1, we create the `Main` class.

* In line 6, we initialize an instance of the `String` class and concatenate it with the other strings in lines $7$ and $8$. Each time the code performs the `+=` operation, a new `String` is created in the `String` pool. 

* In line 9, we display the concatenated `String`. 

* In line 11, we initialize an instance of the `StringBuffer` class. The `StringBuffer` object is altered twice, in lines $12$ and $13$. Each time the code uses the `append()` operation, no new object is created.

* In line 14, we display the concatenated `StringBuffer` object.

In this way, we analyzed the difference between `String` and `StringBuffer` in Java. The `StringBuffer` class can be used to boost performance when you concatenate many strings together in a loop.


What is the difference between String and StringBuffer in Java?

String is immutable and creates new objects on concatenation; StringBuffer is mutable and efficient for repeated modifications.

Parameter	String	StringBuffer
Storage	String pool	Heap memory
Mutability	Immutable	Mutable
Performance	Slower than StringBuffer while performing concatenation	Faster than String while performing concatenation
Length	Fixed	Can be increased
Usage in threaded environment	Not used in a threaded environment	Used in a multi-threaded environment
Synchronization	Not synchronized	Synchronized
Syntax	String variable=”String”; String variable= new String(“String”);	StringBuffer variable= new StringBuffer(“String”);