dap4/d4core/src/main/java/dap4/core/util/DapUtil.java
static public String
    nullify(String path)
    {
        return (path != null && path.length() == 0 ? null : path);
    }
static public String
    nullify(String path)
    {
        return (path != null && path.length() == 0 ? null : path);
    }
Convert "" paths to null

@param path
@return path or null