In Java, both the
String class and the
StringBuffer class are used to work with text data, but they have significant differences in terms of their immutability, performance, and usage. Let's explore the differences between the
String class and the
String: As mentioned earlier, the
String class in Java is immutable, meaning once a
String object is created, its value cannot be changed. Any operation that appears to modify a
String, such as concatenation or substring extraction, actually creates a new
String object with the modified content. This immutability ensures that
String objects are thread-safe, hashable, and can be safely shared among different parts of a program.
StringBuffer: In contrast, the
StringBuffer class is mutable. It allows you to modify its content after creation. You can append, insert, or delete characters in a
StringBuffer without creating new objects. This makes
StringBuffer more efficient when it comes to frequently changing the contents of a string.
String: Due to its immutability, working with
String objects can result in performance overhead when performing operations that create new
String objects, especially in scenarios with frequent modifications or concatenations. Each time you perform an operation on a
String, a new
String object is created, leading to unnecessary memory allocation and garbage collection.
StringBuffer objects are mutable, they are more efficient when it comes to frequent modifications. Appending or modifying the content of a
StringBuffer does not require creating new objects, as the content can be modified directly in the underlying buffer. This makes
StringBuffer more suitable for scenarios where you need to build or modify strings dynamically.
String: As immutable objects,
String instances are inherently thread-safe. Multiple threads can share and read the same
String object without any concerns about concurrent modifications.
StringBuffer class includes built-in synchronization to make it thread-safe. This means multiple threads can safely modify a
StringBuffer object without encountering data corruption. However, this synchronization comes with a performance cost, which makes
StringBuffer less efficient for single-threaded scenarios.
Stringwhen you have a fixed text that doesn't require frequent modifications. For example, when dealing with constants or configuration values.
StringBufferwhen you need to build or modify strings dynamically, especially in multi-threaded environments where thread-safety is required. It is commonly used for string manipulations in performance-critical or concurrent applications.
Java 5 onwards, there's also the
StringBuilder class, which is similar to
StringBuffer but lacks synchronization, making it more efficient in single-threaded scenarios. If you don't need thread-safety,
StringBuilder is often preferred over
StringBuffer due to its better performance.