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.
Matcher matcher = pattern.matcher(value);
            if (!matcher.matches()) {
                throw new IllegalStateException("Invalid " + property + "=\"" + value + "\" contains illegal " +
                        "character, only digit, letter, '-', '_' or '.' is legal.");
            }
        }
    }
    @Parameter(excluded = true)
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    protected void appendAnnotation(Class<?> annotationClass, Object annotation) {
        Method[] methods = annotationClass.getMethods();
        for (Method method : methods) {
            if (method.getDeclaringClass() != Object.class
                    && method.getReturnType() != void.class
                    && method.getParameterTypes().length == 0
                    && Modifier.isPublic(method.getModifiers())
                    && !Modifier.isStatic(method.getModifiers())) {
                try {
                    String property = method.getName();
                    if ("interfaceClass".equals(property) || "interfaceName".equals(property)) {
                        property = "interface";
                    }
                    String setter = "set" + property.substring(0, 1).toUpperCase() + property.substring(1);
                    Object value = method.invoke(annotation);
                    if (value != null && !value.equals(method.getDefaultValue())) {