What do you mean by StringBuffer is a thread safe implementation?

StringBuffer: The Thread-Safe String Builder

In our previous post, we explored StringBuilder, a powerful tool for efficient string manipulation in single-threaded environments. Today, we'll shift our focus to its synchronized cousin, StringBuffer.

What is StringBuffer?

StringBuffer, introduced in Java 1.0, is a mutable string builder class similar to StringBuilder. However, it offers a crucial advantage: thread safety. All methods of StringBuffer are synchronized, meaning only one thread can access and modify the internal state of the object at a time. This synchronization ensures consistent behavior in multithreaded environments, preventing race conditions and unexpected results.

When to Use StringBuffer?

StringBuffer becomes the go-to choice when:

• You're working with multiple threads that might concurrently modify the same string.

• Thread safety is supreme, and you can tolerate a slight performance overhead.

Why is StringBuffer Synchronized?

The synchronized nature of StringBuffer ensures that it can be safely used in multi-threaded environments. Synchronization means that only one thread can modify the StringBuffer instance at a time, preventing race conditions and ensuring consistent results.

StringBuffer vs. StringBuilder

• StringBuffer: Synchronized and thread-safe.

• StringBuilder: Non-synchronized and not thread-safe, but faster in single-threaded scenarios.

Example of Creating Mutable String with StringBuffer :

When you use StringBuffer in a multithreaded environment, it adds synchronization behavior, which avoids inconsistent output.

Since StringBuffer is synchronized, multiple threads modifying it concurrently will not cause race conditions. The expected length of the StringBuffer should be 3000 (1000 * 3), and the content should consistently include 1000 'A's, 1000 'B's, and 1000 'C's, in order like "AABBCC" not like "ABAC".

Conclusion

This example demonstrates the synchronized nature of StringBuffer. When used in a multi-threaded environment, StringBuffer ensures thread safety, providing consistent and expected results. If thread safety is not a concern, StringBuilder can be used for better performance.