import java.util.Random;

public class StringBufferVsSringBuilder {
	public static int demo(final Object stringJoiner, final int testCount) throws InterruptedException {
		ThreadGroup group = new ThreadGroup(stringJoiner.getClass().getName() + "@" + stringJoiner.hashCode());
		final Random rand = new Random();

		Runnable listAppender = new Runnable() {
			public void run() {
				try {
					Thread.sleep(rand.nextInt(2));
				} catch (InterruptedException e) {
					return;
				}
				if (stringJoiner instanceof StringBuffer) {
					((StringBuffer)stringJoiner).append("0");
				} else if (stringJoiner instanceof StringBuilder) {
					((StringBuilder)stringJoiner).append("0");
				}
			}
		};

		for (int i = 0; i < testCount; i++) {
			new Thread(group, listAppender, "InsertList-" + i).start();
		}

		while (group.activeCount() > 0) {
			Thread.sleep(10);
		}

		return stringJoiner.toString().length();
	}

	public static void main(String[] args) throws InterruptedException {
		StringBuilder stringBuilder = new StringBuilder();
		StringBuffer stringBuffer = new StringBuffer();
		final int N = 10000;
		for (int i = 0; i < 10; i++) {
			stringBuilder.delete(0, stringBuilder.length());
			stringBuffer.delete(0, stringBuffer.length());
			int builderLength = demo(stringBuilder, N);
			int bufferLength = demo(stringBuffer, N);
			System.out.println("StringBuilder/StringBuffer: " + builderLength + "/" + bufferLength);
		}
	}
}