Three ways to do this:

• Decimal Format
• String.format
• BigDecimal

Decimal Format

import java.math.RoundingMode;
import java.text.DecimalFormat;

public class DecimalFormatDemo {
    private static DecimalFormat df = new DecimalFormat("#.###");

    public static void main(String[] args) {

        double input = 1.23456789;
        System.out.println(df.format(input));

        df.setRoundingMode(RoundingMode.DOWN);
        System.out.println(df.format(input));

        df.setRoundingMode(RoundingMode.UP);
        System.out.println(df.format(input));
    }
}

Output

1.235
1.234
1.235

String.format

 double input = 1.23456789;
 System.out.println("double : " + String.format("%.2f", input));
 System.out.format("double : %.2f", input);

Output

double : 1.23
double : 1.23

BigDecimal

double input = 1.23456789;
System.out.println("double : " + input);

BigDecimal bd = new BigDecimal(input).setScale(2,RoundingMode.HALF_UP);
double newInput = bd.doubleValue();

System.out.println("double : " + newInput);

Output

double : 1.23456789
double : 1.23