cannot read double value if cell is empty

[takeAction]

I am using jxls 2.14.0 and jxls-reader 2.1.0, commons-beanutils 1.9.4, the java code is:

XLSReader mainReader = ReaderBuilder.buildFromXML(xmlConfig);

mainReader.getConvertUtilsBeanProvider().getConvertUtilsBean().register(new JxlsDateConverter(),
				java.util.Date.class);

ReaderConfig.getInstance().setUseDefaultValuesForPrimitiveTypes(true);
XLSReadStatus readStatus = mainReader.read( dataInputStream, beanMap);

there is double value type in excel template and value left empty, and the java type is Double.

The tester told me that our system throws an exception saying that cannot read this cell value when it is empty in the test server.

I can repeat this problem in my local pc, I tried to debug and found that in AbstractConverter of commons-beanutils:

protected <T> T handleMissing(final Class<T> type) {

        if (useDefault || type.equals(String.class)) {
            ....
            // value is now either null or of the desired target type
            return type.cast(value);
        }

        final ConversionException cex =  new ConversionException("No value specified for '" +
                toString(type) + "'");

the useDefault is false, so it skip this if and throws ConversionException.

I can repeat this problem in my pc many times.

However, when I debug, the tester told me that he cannot repeat again without any code changed. Meanwhile, after I added break point on super of

public DoubleConverter(final Object defaultValue) {
        super(true, defaultValue);
}

and click step into in debug until read process finished, I also cannot repeat this problem any more in my local pc, very strange. Then I remove break point of DoubleConverter, I still cannot repeat this problem.

it seems that this problem disappear after I click step into from DoubleConverter.