StringBuilder and StringBuffer in Java

Introduction

StringBuilder and StringBuffer are classes in Java used to create mutable (modifiable) string objects. Unlike the immutable String class, these classes allow modification of string content without creating new objects.

Differences Between StringBuilder and StringBuffer

Feature StringBuilder StringBuffer
Thread Safety Not thread-safe (faster). Thread-safe (slower).
Performance Better performance in single-threaded environments. Better suited for multi-threaded environments.
Usage Use when thread safety is not required. Use when thread safety is required.

1. Using StringBuilder

Example: Appending Strings

    public class StringBuilderExample {
        public static void main(String[] args) {
            StringBuilder sb = new StringBuilder("Hello");
            sb.append(" World");
            System.out.println("StringBuilder result: " + sb.toString()); // Output: Hello World
        }
    }

Example: Inserting and Reversing

    public class StringBuilderAdvancedExample {
        public static void main(String[] args) {
            StringBuilder sb = new StringBuilder("Java");
            sb.insert(4, " Programming");
            System.out.println("After insertion: " + sb.toString()); // Output: Java Programming
    
            sb.reverse();
            System.out.println("After reversing: " + sb.toString()); // Output: gnimmargorP avaJ
        }
    }

2. Using StringBuffer

Example: Appending Strings

    public class StringBufferExample {
        public static void main(String[] args) {
            StringBuffer sb = new StringBuffer("Hello");
            sb.append(" World");
            System.out.println("StringBuffer result: " + sb.toString()); // Output: Hello World
        }
    }

Example: Deleting and Replacing

    public class StringBufferAdvancedExample {
        public static void main(String[] args) {
            StringBuffer sb = new StringBuffer("Hello Java");
            sb.delete(5, 10);
            System.out.println("After deletion: " + sb.toString()); // Output: Hello
    
            sb.replace(0, 5, "Hi");
            System.out.println("After replacement: " + sb.toString()); // Output: Hi
        }
    }

3. Conclusion

Both StringBuilder and StringBuffer are powerful tools for handling mutable strings in Java:

  • Use StringBuilder when you do not need thread safety.
  • Use StringBuffer when thread safety is required.

Understanding the differences and use cases of these classes can help optimize your code.




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