如何在Java中使用GSON将无名对象转换为JSON？

Question

I was writing a program to return JSON object using gson and I discovered something peculiar. Basically when I wanted to convert following object to JSON it gave me null.

Customer customer = new Customer() {
    {
        setId(1);
        setName("Foo bar");
        setAddress("Some Address");
    }
};
System.out.println(gson.toJson(customer));

where Customer looks like this

public class Customer{
    int id;
    String name;
    String address;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }   
}

but when I created object properly like

Customer customer = new Customer();
customer.setId(1);
customer.setName("Foo bar");
customer.setAddress("Some Address");
System.out.println(gson.toJson(customer));

it worked perfectly fine and gave output as supposed to. Why does it matter how I create my objects. Is there difference between two methods?

Answer 1

The reason the first case it is returning null because 'customer' object's class is an anonymous one which clazz.isAnonymousClass() return true

See below for GSon implementation