import java.math.BigDecimal;
import java.math.MathContext;
import java.text.ParseException;

public class NumberUtils {
  public static Double fractionToDouble(String fraction)
  throws ParseException {
      Double d = null;
      if (fraction != null) {
          if (fraction.contains("/")) {
              String[] numbers = fraction.split("/");
              if (numbers.length == 2) {
                  BigDecimal d1 = BigDecimal.valueOf(Double.valueOf(numbers[0]));
                  BigDecimal d2 = BigDecimal.valueOf(Double.valueOf(numbers[1]));
                  BigDecimal response = d1.divide(d2, MathContext.DECIMAL128);
                  d = response.doubleValue();
              }
          }
          else {
              d = Double.valueOf(fraction);
          }
      }
      if (d == null) {
          throw new ParseException(fraction, 0);
      }
      return d;
  }

  public static void main(String[] args) throws Exception{
    System.out.println(NumberUtils.fractionToDouble("1/2"));
    System.out.println(NumberUtils.fractionToDouble("2/3"));
    System.out.println(NumberUtils.fractionToDouble("4/6"));
    System.out.println(NumberUtils.fractionToDouble("4/5"));
    System.out.println(NumberUtils.fractionToDouble("3/9"));

    /*
     * 0.5
     * 0.6666666666666666
     * 0.6666666666666666
     * 0.8
     * 0.3333333333333333
     */
  }
}