In Java, the StringBuffer class is part of the java.lang package and provides a mutable sequence of characters. This means you can modify the content of a StringBuffer object without creating a new object each time a modification is made. The StringBuffer class is similar to the String class, but it is mutable, whereas String objects are immutable.
Here are some key points about StringBuffer:
Mutable: Unlike strings, which are immutable in Java, StringBuffer allows you to modify the contents of the string without creating a new object.
Synchronization: StringBuffer is thread-safe, meaning it’s designed to be used by multiple threads concurrently without causing data inconsistency issues. However, this comes at the cost of performance, as the methods are synchronized.
Performance Implications: While StringBuffer provides thread safety, it can be less efficient than its non-synchronized counterpart, StringBuilder, which was introduced in Java 5. If you don’t need thread safety, it’s generally recommended to use StringBuilder for better performance.
These are just a few examples of the methods provided by StringBuffer. Remember, if you don’t need thread safety, you may prefer to use StringBuilder for better performance in a non-threaded environment.
Feature
String
StringBuilder
StringBuffer
Immutability
Immutable
Mutable
Mutable
Thread-Safety
Not applicable (immutable)
Not synchronized (not thread-safe)
Synchronized (thread-safe)
Performance (single-threaded)
Good for constant strings, but concatenation can be expensive due to new object creation
Faster for concatenations as it doesn’t create intermediate objects
Similar performance to StringBuilder but with synchronization overhead
Synchronization
Not applicable (immutable)
Not synchronized
Synchronized
Use Case
Use when you need immutability, or when creating constant strings
Use for high-performance string manipulation in a single-threaded context
Use for string manipulation in a multi-threaded context where thread-safety is required
Memory Usage
Higher for concatenation due to multiple intermediate objects
More efficient memory usage compared to String for concatenation
Similar to StringBuilder but with additional memory overhead for synchronization
