udunits/src/main/java/ucar/units/DerivedUnitImpl.java
private static UnitName dimensionlessID() {
        UnitName id;
        try {
            id = UnitName.newUnitName("1", "1", "1");
        }
        catch (final NameException e) {
            id = null;
        }
        return id;
    }
private static UnitName dimensionlessID() {
        UnitName id;
        try {
            id = UnitName.newUnitName("1", "1", "1");
        }
        catch (final NameException e) {
            id = null;
        }
        return id;
    }
Returns the identifiers associated with the dimensionless, derived unit.

@return The identifiers of the dimensionless, derived unit.