String-StringBuilder-StringBuffer

A simple Java project demonstrating the differences between String, StringBuilder, and StringBuffer — covering immutability, mutability, synchronization, and performance.

📌 String

• Immutable Class → Once a String object is created, it cannot be changed.
• Every modification creates a new object in the String pool.
• Suitable when the data is not frequently modified.
• Thread-Safe because it is immutable.

Example:

String s = "Hello"; s.concat(" World"); System.out.println(s); // Output: Hello (not Hello World)

##📌 StringBuilder

• Mutable Class → Can be modified without creating new objects.
• Introduced in Java 1.5.
• Not synchronized → Better performance in single-threaded environments.
• Faster than both String and StringBuffer.

Example:

StringBuilder sb = new StringBuilder("Hello"); sb.append(" World"); System.out.println(sb); // Output: Hello World

###📌 StringBuffer

• Mutable Class → Can be modified without creating new objects.
• Synchronized → Thread-safe but slower than StringBuilder.
• Used in multi-threaded environments when thread safety is required.

Example:

StringBuffer sbf = new StringBuffer("Hello"); sbf.append(" World"); System.out.println(sbf); // Output: Hello World

Feature	String (Immutable)	StringBuilder (Mutable)	StringBuffer (Mutable)
Mutability	❌ Immutable	✅ Mutable	✅ Mutable
Thread-Safe	✅ Yes	❌ No	✅ Yes
Performance	❌ Slow	✅ Fastest	⚠️ Slower than StringBuilder
Use Case	Fixed data, keys	Single-threaded apps	Multi-threaded apps

🚀 Conclusion

• Use String when values don’t change often.
• Use StringBuilder for single-threaded applications with lots of modifications.
• Use StringBuffer for multi-threaded applications where thread safety is required.