StringBuffer and StringBuilder

In Java, both StringBuffer and StringBuilder are classes used to create and manipulate mutable strings (unlike String, which is immutable).

Here’s the comparison:

🔑 1. Mutability

• Both StringBuffer and StringBuilder create mutable string objects (content can be changed without creating new objects).

🔑 2. Thread Safety

• StringBuffer
  • Thread-safe, because its methods are synchronized.
  • Suitable for multi-threaded environments.
  • Slightly slower due to synchronization overhead.
• StringBuilder
  • Not thread-safe (no synchronization).
  • Suitable for single-threaded environments.
  • Faster than StringBuffer.

🔑 3. Performance

• StringBuffer → Slower (due to synchronization).
• StringBuilder → Faster (no synchronization).

🔑 4. Example

public class Test {
    public static void main(String[] args) {
        // Using StringBuffer
        StringBuffer sb1 = new StringBuffer("Hello");
        sb1.append(" World");
        System.out.println("StringBuffer: " + sb1);

        // Using StringBuilder
        StringBuilder sb2 = new StringBuilder("Hello");
        sb2.append(" World");
        System.out.println("StringBuilder: " + sb2);
    }
}

public class Test {
    public static void main(String[] args) {
        // Using StringBuffer
        StringBuffer sb1 = new StringBuffer("Hello");
        sb1.append(" World");
        System.out.println("StringBuffer: " + sb1);

        // Using StringBuilder
        StringBuilder sb2 = new StringBuilder("Hello");
        sb2.append(" World");
        System.out.println("StringBuilder: " + sb2);
    }
}

✅ Output:

StringBuffer: Hello World
StringBuilder: Hello World

StringBuffer: Hello World
StringBuilder: Hello World

🔑 5. When to Use

• Use StringBuffer if:
  • Multiple threads may access/modify the string simultaneously.
• Use StringBuilder if:
  • Only a single thread will modify the string (most common case).