How to modify an existing System.out.println

Question

If I run this code

public class main 
{
    public static void main(String[] args)
    {
        teste(20);
    }

    public static void teste(int maximo)
    {
        for(int i = 0; i < maximo; i++)
        {
            System.out.println(i + " de " + maximo);    
        }
    }
}

he’s gonna print that

0 de 30
1 de 30
2 de 30
3 de 30
4 de 30
5 de 30
6 de 30
7 de 30
8 de 30
9 de 30
10 de 30
11 de 30
12 de 30
13 de 30
14 de 30
15 de 30
16 de 30
17 de 30
18 de 30
19 de 30
20 de 30

but I would like instead of the line repeating itself 20 times just modify the first.

If you could give me an API that can run this would also help.

Answer 1

Use System.out.print() and the escape character \r at the end of the text:

public static void teste(int maximo)
{
    for(int i = 0; i < maximo; i++)
    {
        System.out.print(i + " de " + maximo + "\r");    
    }
}

Instead of System.out.println(), who makes line change after the display, System.out.print() always print on the same line.
The character of escape \r causes the cursor to return to the beginning of the line.

The escape character is ignored by console of Eclipse, will therefore have to execute the program in a command window windows.

The way the code is you won’t be able to see anything, since the window will be opened and closed almost immediately.
To test enter the following changes:

public class App 
{
    public static void main(String[] args)
    {
        teste(4);
    }
    public static void teste(int maximo)
    {
        for(int i = 0; i < maximo; i++)
        {
            System.out.print(i + " de " + maximo + "\r");    
            try {
                //Espera meio segundo antes de prosseguir
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("\r\n");
        Scanner keyboard = new Scanner(System.in);
        //Espera que uma tecla seja premida antes de sair do programa
        String tecla = keyboard.next();     
    }
}

Answer 2

If the intention is to show only the last result, then you can set a variable and run the System.out.print in the end:

private string resultadoFinal:

...

public static void teste(int maximo)
{
    for(int i = 0; i < maximo; i++)
    {
           resultadoFinal = i + " de " + maximo;
    }
}

System.out.print(resultadoFinal);

However if the execution is not within a loop and this code is illustrative only and still assuming the output sent or output will be asynchronous, so it’s like @Ramaral said, Eclipse won’t work using \r