How would you differentiate between a String, StringBuffer, and a StringBuilder?
In Java, String
, StringBuffer
, and StringBuilder
are all classes used to handle strings, but they have different characteristics and use cases. Here’s a breakdown of their differences:
String
objects are immutable, meaning once a String
is created, it cannot be changed. Any modification to a String
results in the creation of a new String
object.String
when you have a fixed set of characters that do not change, or when you are performing a small number of modifications.String str = "Hello";
str = str + " World"; // Creates a new String object
StringBuffer
objects are mutable, meaning you can modify the contents of a StringBuffer
without creating a new object.StringBuffer
is synchronized, making it thread-safe. This means that it can be safely used in a multi-threaded environment.String
for multiple modifications, the synchronization can introduce overhead, making it slower than StringBuilder
in single-threaded scenarios.StringBuffer
when you need a mutable string in a multi-threaded environment.StringBuffer sb = new StringBuffer("Hello");
sb.append(" World"); // Modifies the existing StringBuffer object
StringBuffer
, StringBuilder
objects are mutable.StringBuilder
is not synchronized, which means it is not thread-safe. This makes it faster than StringBuffer
in single-threaded scenarios.StringBuilder
is preferred for string manipulation in a single-threaded context due to its better performance.StringBuilder
when you need a mutable string and you are sure that the code will not be accessed by multiple threads simultaneously.StringBuilder sb = new StringBuilder("Hello");
sb.append(" World"); // Modifies the existing StringBuilder object
Choosing the right one depends on your specific use case, particularly regarding mutability and thread safety.