public class StringPerformance { // Define class to benchmark string manipulation efficiency
    public static void main(String[] args) { // Entry point for the performance benchmark
        int iterations = 20000; // Define number of times to perform string concatenation
        System.out.println("--- String Benchmarking (" + iterations + " loops) ---"); // Print header
        
        // 1. Immutable String Test
        long start = System.currentTimeMillis(); // Record start time in milliseconds
        String s = ""; // Initialize an empty immutable string
        for (int i = 0; i < iterations; i++) { // Loop twenty thousand times
            s += "a"; // Append 'a' using concatenation (creates new object every time)
        } // End of the slow loop
        long end = System.currentTimeMillis(); // Record the end time
        System.out.println("String (Immutable) time: " + (end - start) + "ms"); // Print total duration
        
        // 2. Mutable StringBuilder Test (Single-threaded optimized)
        start = System.currentTimeMillis(); // Reset the start timer
        StringBuilder sb = new StringBuilder(); // Initialize a mutable string builder object
        for (int i = 0; i < iterations; i++) { // Loop twenty thousand times
            sb.append("a"); // Append 'a' directly to existing memory buffer
        } // End of the fast loop
        end = System.currentTimeMillis(); // Record the end time
        System.out.println("StringBuilder (Mutable) time: " + (end - start) + "ms"); // Print total duration
        
        // 3. Mutable StringBuffer Test (Thread-safe)
        start = System.currentTimeMillis(); // Reset the start timer
        StringBuffer sbuf = new StringBuffer(); // Initialize a thread-safe mutable buffer
        for (int i = 0; i < iterations; i++) { // Loop twenty thousand times
            sbuf.append("a"); // Append 'a' directly to synchronized buffer
        } // End of the thread-safe loop
        end = System.currentTimeMillis(); // Record the end time
        System.out.println("StringBuffer (Thread-safe) time: " + (end - start) + "ms"); // Print total duration
        
        System.out.println("\nConclusion: Immutable Strings are significantly slower in loops."); // Log result
        System.out.println("Benchmarking Complete."); // Final log for program exit
    } // End of main method
} // End of StringPerformance class