Why Using isSuccess Can Break JSON Serialization in Java and How to Fix It

In daily development we often define boolean fields in classes, e.g., a field indicating whether a request succeeded.

Developers use different naming conventions such as success or isSuccess, and IDEs often generate isSuccess getters automatically.

According to the JavaBeans Specification, a normal property propertyName has getters/setters getPropertyName() and setPropertyName(...). For boolean properties the getter is isPropertyName() and the setter remains setPropertyName(...).

public <PropertyType> get<PropertyName>();
public void set<PropertyName>(<PropertyType> a);

For a boolean property the signatures become:

public boolean is<PropertyName>();
public void set<PropertyName>(boolean m);

If the property is named success, the getter should be isSuccess (or getSuccess) and the setter setSuccess. If the property itself is named isSuccess, the getter would be isIsSuccess or getIsSuccess, which is confusing.

Consider the following JavaBean:

class Model implements Serializable {
    private static final long serialVersionUID = 1836697963736227954L;
    private boolean isSuccess;

    public boolean isSuccess() { return isSuccess; }
    public void setSuccess(boolean success) { isSuccess = success; }
    public String getHollis() { return "hollischuang"; }
}

When this class is serialized with different JSON libraries, the results differ:

Serializable Result With fastjson :{"hollis":"hollischuang","success":true}
Serializable Result With Gson :{"isSuccess":true}
Serializable Result With jackson :{"success":true,"hollis":"hollischuang"}

Fastjson and Jackson inspect getter methods, treat isSuccess as a property named success, and therefore output "success". Gson, on the other hand, inspects fields directly and outputs the original field name "isSuccess".

Consequently, if an object serialized by fastjson (or Jackson) is deserialized by Gson, the isSuccess field will be missing and default to false, which can cause serious bugs in production.

To avoid this inconsistency, the recommendation is to name the field success and keep the getter isSuccess. This follows the JavaBeans convention and yields identical results across all major JSON serialization frameworks.