Day 19: StringBuffer and StringBuilder in Java:

Mutable String: A String that can be modified or changed is known as mutable String.

StringBuffer and StringBuilder are classes in Java used for creating and manipulating mutable strings. Unlike String, which is immutable, both StringBuffer and StringBuilder allow modifications to the content of strings without creating new objects.

StringBuffer

1. Thread Safety: All methods in StringBuffer are synchronized, making it thread-safe for multi-threaded environments.
2. Performance: Slightly slower compared to StringBuilder due to the overhead of synchronization.

Example: Using StringBuffer

StringBuilder

1. Thread Safety: StringBuilder is not synchronized, meaning it is not thread-safe.
2. Performance: Faster than StringBuffer in single-threaded environments due to the absence of synchronization.

Example: Using StringBuilder

When to Use

• Use StringBuffer when working in a multi-threaded environment where multiple threads may access and modify the same string.
• Use StringBuilder in a single-threaded environment for better performance, as it avoids the overhead of synchronization.

Methods Common to Both

• append(String str): Adds the specified string to the end.
• insert(int offset, String str): Inserts the string at the specified position.
• replace(int start, int end, String str): Replaces content within a specified range.
• delete(int start, int end): Removes content within a specified range.
• reverse(): Reverses the string.
• capacity(): Returns the current capacity of the buffer.
• ensureCapacity(int minimumCapacity): Ensures that the capacity is at least equal to the specified value.

So when to use what?

• Use String when immutability is needed.
• Use StringBuffer for thread-safe, mutable strings.
• Use StringBuilder for mutable strings in a single-threaded environment for better performance.

Happy Learning :)