Correcting a bug in the JRE classes

Question

I have run across a bug in the class java.text.DecimalFormat
I am using JSE 1.3.1_04, Windows XP professional o.s.
The bug resides in the following method:
public StringBuffer format(double number, StringBuffer
result, FieldPosition fieldPosition)
The following line of code within the abovementioned
method will produce a "hotspot divide by zero error",
if the variable named "number" contains a value of zero.
boolean isNegative = (number < 0.0) || (number == 0.0 &&
1/number < 0.0);
I would like to repair this bug "in place" (actually change the line of code in error), and return the fixed class to the java.text package. How can I do this? I have extracted the source from the src.jar file, made the change, and now I need to replace the older version of this class.
BTW, I have submitted a bug report, however, I cannot wait for the fix.

Answer 1

Anyways, here is my somewhat "hacked" version of DecimalFormat.java to bypass the problem. Just make sure the following program resides in a directory that precedes the "rt.jar" file in the classpath.
import java.text.FieldPosition;
* A convenenience class to override the default implementation of DecimalFormat.
* This is purely a "workaround" to avoid the "divide by zero" error that is occasionally
* issued by the HotSpot  compiler.  See #format(double value) method for details
* When (and if) there is a problem resolution in a future release, this program should be disabled
* @author Stuart Leonard
* @version 1.0
* @since 09/08/2002
class DecimalFormat
    private java.text.DecimalFormat decfmt;
    private String dft = "";
    private static final char       PATTERN_DIGIT              = '#';
     * The public constructor for this class.  Accepts a pattern to be used
     * by a java.text.DecimalFormat object
     * @param fmt The pattern to be used
    public DecimalFormat(String fmt)
        decfmt = new java.text.DecimalFormat(fmt);
        // check to see if last position of pattern is zero
        // if so, initialize a "zero balance" default pattern.
        if (fmt != null && fmt.length() > 0)
            StringBuffer strbuf = new StringBuffer(fmt);
            int endPos = strbuf.length()-1;
            if (strbuf.charAt(endPos) == '0')
                int begPos = endPos;
                for (int i = endPos; i>0; i--)
                    char chr = strbuf.charAt(i);
                    if (chr == PATTERN_DIGIT)
                        begPos = i+1;
                        break;
                dft = strbuf.substring(begPos, endPos+1);
     * An overridden implementation of #java.text.NumberFormat.format(double)
     * If value is zero, then initialize return value with a blank suppressed
     * "zero balance" value, as specified by the original format pattern.
     * @param value The incoming double value to be formatted by a string pattern
     * @return The incoming value represented as a string pattern
    public String format (double value)
        String formatted = dft;
        if (value != 0)
            formatted = decfmt.format(value);
        return formatted;   
     * An overridden implementation of #java.text.DecimalFormat.format(double, StringBuffer, FieldPosition)
     * If value is zero, then initialize return value with a blank suppressed
     * "zero balance" value, as specified by the original format pattern.
     * Formats a double to produce a string.
     * @param number    The double to format
     * @param toAppendTo    where the text is to be appended
     * @param fieldPosition    On input: an alignment field, if desired.
     * On output: the offsets of the alignment field.
     * @return The value passed in as the result parameter
     * @see java.text.FieldPosition
    public StringBuffer format(double number, StringBuffer result,
                               FieldPosition fieldPosition)
        StringBuffer strbuf = new StringBuffer();
        if (number != 0)
            strbuf = decfmt.format(number, result, fieldPosition);
        else   
            strbuf.append(dft);
        return strbuf;   
     * The default implementation of #java.text.NumberFormat.format(long)
     * This exists ONLY because of the "divide by zero" error that
     * is being issued by #java.text.DecimalFormat.format(double, String Buffer, FieldPosition)
     * @param value The incoming value to be formatted by a string pattern
     * @return The incoming value represented as a string pattern
    public String format (long value)
          return decfmt.format(value);
     * The default implementation of #java.text.DecimalFormat.format(long, StringBuffer, FieldPosition)
     * This exists ONLY because of the "divide by zero" error that
     * is being issued by #java.text.DecimalFormat.format(double, String Buffer, FieldPosition)
     * Format a long to produce a string.
     * @param number    The long to format
     * @param toAppendTo    where the text is to be appended
     * @param fieldPosition    On input: an alignment field, if desired.
     * On output: the offsets of the alignment field.
     * @return The value passed in as the result parameter
     * @see java.text.FieldPosition
    public StringBuffer format(long number, StringBuffer result,
                               FieldPosition fieldPosition)
        return decfmt.format(number, result, fieldPosition);