How to Convert Firebase JSON to Java Objects When Encountering \'Failed to Bounce to Type\' Error?

Unable to Convert Firebase JSON to Java Objects

Your Firebase database contains a JSON structure with user data. You're attempting to convert this JSON into Java objects using the Java class User, but you're encountering the "Failed to bounce to type" error.

Understanding the Error

This error indicates that Jackson, the library used by Firebase for serialization and deserialization, encountered a problem mapping your JSON data to your Java class.

Solution: Complete Object Mapping

One approach is to create a Java class (User) that fully matches the properties in your JSON. This means creating a User class with fields handle, name, and stackId. With this approach, Jackson can automatically map the JSON properties to the Java class properties.

Partially Loading Objects

If you only need a subset of the user data, such as handle and name, you can create a User class that omits stackId. However, you'll need to use the @JsonIgnoreProperties annotation to instruct Jackson to ignore the missing property in the JSON.

Partially Saving Objects

You may also encounter issues when saving objects to Firebase if your Java class has additional methods that are not reflected in the JSON. To prevent Jackson from serializing these methods, annotate them with @JsonIgnore.

Code Sample: Partial Loading with Jackson Annotations

@JsonIgnoreProperties({ "stackId" })
private static class User {
    String handle;
    String name;

    public String getHandle() { return handle; }
    public String getName() { return name; }

    @Override
    public String toString() { return "User{handle='" + handle + "', name='" + name + "'}"; }
}

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