Steps:
Tests number format consistency between CLDR and Java, using 0.56 as input.
For example: on locale pt_PT. The pattern of decimalFormat is "#.##0,###" (group is "." and decimal is ",") in CLDR pt.xml file.
To compare the output format between CLDR and Java, by running below code.

public void javaNumberOutput() {
    String a="0.56";
    Locale target = Locale.forLanguageTag("pt-PT");

    double d = Double.valueOf(a).doubleValue();
    String outString = NumberFormat.getNumberInstance(target).format(d);
    System.out.println("expected:" + outString);
}

Result:
Following CLDR decimalFormat, the output should be 0,56, but actually the output of below code is 0$56.