📘 Lesson · Lesson 37

String vs StringBuffer vs StringBuilder

Three String Types

String is immutable (cannot change). StringBuffer and StringBuilder are mutable (can change) — better for many edits.

Type	Mutable	Thread-safe	Speed
String	No	-	-
StringBuffer	Yes	Yes	slower
StringBuilder	Yes	No	fastest

StringBuilder sb = new StringBuilder("Hello");
sb.append(" World");   // modifies same object
System.out.println(sb);   // Hello World

Hello World

String = immutable; StringBuffer = mutable + thread-safe; StringBuilder = mutable + fastest.
Use StringBuilder for many string edits in single-threaded code.

String immutable है (बदल नहीं सकते)। StringBuffer और StringBuilder mutable हैं (बदल सकते हैं) — बहुत edits के लिए बेहतर।

Type	Mutable	Thread-safe	Speed
String	नहीं	-	-
StringBuffer	हाँ	हाँ	धीमा
StringBuilder	हाँ	नहीं	सबसे तेज़

StringBuilder sb = new StringBuilder("Hello");
sb.append(" World");   // same object modify करता है
System.out.println(sb);   // Hello World

Hello World

String = immutable; StringBuffer = mutable + thread-safe; StringBuilder = mutable + सबसे तेज़।
Single-threaded code में बहुत string edits को StringBuilder use करें।