Medindo o tempo de execução de métodos. Classe de teste.

Main.java

public class Main {
	public static void main(String[] args) throws InterruptedException {
		TimerLogger timerLoger = new TimerLogger();
		
		timerLoger.start();
		for (int i = 0; i < 10; i++) {
			Thread.sleep(1000);
			timerLoger.partial();
		}
		timerLoger.end();
		
		System.out.println("---------------------------");
		timerLoger.start("classe Main");
		for (int i = 0; i < 10; i++) {
			Thread.sleep(1000);
			timerLoger.partial("um metodo");
		}
		timerLoger.end("outro lugar");
	}
}

TimerLogger.java

/**
 * @author Gabriel Rubens - http://gabrielrubens.com.br
  * Apenas um teste de tempo de execução de metodos
 */
public class TimerLogger {
	private static final String NOW = "Now";
	public long timer;
	
	public void start(){
		this.start(NOW);
	}
 
	public void start(String label){
		this.timer = currentTimeMillis();
		this.print(formatLabel(label), timer);
	}
 
	public void partial(){
		this.partial("");
	}
 
	public void partial(String label){
		long partial = currentTimeMillis();
		this.print(formatLabel(label), partial - this.timer);
	}
	
	public void end(){
		this.end(NOW);
	}
 
	public void end(String label){
		long end = currentTimeMillis();
		this.print("end\t", end - this.timer);
		this.print(formatLabel(label), currentTimeMillis());
	}
 
	private String formatLabel(String label) {
		if(label.isEmpty()) return "";
		
		return label + " - ";
	}
	
	private void print(String label, long timerPrint){
		int hours   = (int) ((timerPrint / (1000*60*60)) % 24);
		int minutes = (int) ((timerPrint / (1000*60)) % 60);
		int seconds = (int) (timerPrint / 1000) % 60 ;
		int milliseconds = (int) (timerPrint / 1000);
		System.out.println(String.format("%s%d h, %d min, %d sec, %d mil",
							label, hours, minutes, seconds, milliseconds));
	}
	
	private long currentTimeMillis() {
		return System.currentTimeMillis();
	}
}