Intellij Idea's debugger renders object to string in object view (Preferences -> Build, Execution, Deployment -> Debugger -> Data Views -> Java -> Enable 'toString()' object view). This behavior is enabled by default and it leads some strange problem when debug in Dubbo, for examples: #2431, or user may observe a ReferenceConfig may init twice or ReferenceConfig#urls may have two same entries if the breakpoint happens to set in the relevant places. You may interested in looking into the details from http://t.cn/EAhta27, where @code4wt gives the excellent analysis.
if (legacyKey != null && legacyKey.length() > 0) {
                                        value = convertLegacyValue(legacyKey, ConfigUtils.getProperty(legacyKey));
                                    }
                                }
                            }
                        }
                    }
                    if (value != null && value.length() > 0) {
                        method.invoke(config, convertPrimitive(method.getParameterTypes()[0], value));
                    }
                }
            } catch (Exception e) {
                logger.error(e.getMessage(), e);
            }
        }
    }
    private static String getTagName(Class<?> cls) {
        String tag = cls.getSimpleName();
        for (String suffix : SUFFIXES) {
            if (tag.endsWith(suffix)) {
                tag = tag.substring(0, tag.length() - suffix.length());
                break;
            }
        }
        tag = tag.toLowerCase();
        return tag;
    }
    protected static void appendParameters(Map<String, String> parameters, Object config) {
        appendParameters(parameters, config, null);
    }