FULL PRODUCT VERSION :
java version "1.4.2_03"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_03-b02)
Java HotSpot(TM) Client VM (build 1.4.2_03-b02, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
DecimalFormat will return non-floating-point objects (e.g. Long) for patterns containing a minimum number fraction digits greater than zero (getMinimumFractionDigits), when parsing whole numbers. The behavior I would expect would be to return a Double/Float of the given whole number.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run test case.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I would expect the type of the returned object to be a floating-point type like Float or Double. Instead it returns a Long.
ACTUAL -
The object returned is of type 'Long'

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.text.DecimalFormat;

public class TestDecimalFormat {
  public static void main(String[] args) throws Exception {
    // provide a decimal format with a mandatory fraction digit
    DecimalFormat format = new DecimalFormat("#,##0.0#");
    // sanity check here
    System.out.println("isParseIntegerOnly? " + format.isParseIntegerOnly());
    // if getMinimumFractionDigits is non-zero, I would expect the object returned
    // to be a floating-point type, i.e. Float or Double
    System.out.println("getMinimumFractionDigits()? " + format.getMinimumFractionDigits());
    
    // this is a whole number, however the fraction is mandatory in the above pattern
    // so we would expect a floating-point type to be returned
    String number = "123.0";
    Object o = format.parseObject(number);
    System.out.println("Parsed value: " + o);
    System.out.println("Parsed value class (expect floating point): " + o.getClass());
  }
}
---------- END SOURCE ----------