Retrofit 1.9.0すべてのフィールドにJSONが入力されない

JSONフォームhttp://httpbin.org/getを取得しようとしています。Retrofit 1.9.0すべてのフィールドにJSONが入力されない

-----------------------------------com.app.apitest.test.Args.java----------------------------------- 

package com.app.apitest.test; 


public class Args { 


} 
-----------------------------------com.app.apitest.test.Example.java----------------------------------- 

package com.app.apitest.test; 

import com.google.gson.annotations.Expose; 
import com.google.gson.annotations.SerializedName; 

public class Example { 

@SerializedName("args") 
@Expose 
private Args args; 
@SerializedName("headers") 
@Expose 
private Headers headers; 
@SerializedName("origin") 
@Expose 
private String origin; 
@SerializedName("url") 
@Expose 
private String url; 

public Args getArgs() { 
return args; 
} 

public void setArgs(Args args) { 
this.args = args; 
} 

public Headers getHeaders() { 
return headers; 
} 

public void setHeaders(Headers headers) { 
this.headers = headers; 
} 

public String getOrigin() { 
return origin; 
} 

public void setOrigin(String origin) { 
this.origin = origin; 
} 

public String getUrl() { 
return url; 
} 

public void setUrl(String url) { 
this.url = url; 
} 

} 
-----------------------------------com.app.apitest.test.Headers.java----------------------------------- 

package com.app.apitest.test; 

import com.google.gson.annotations.Expose; 
import com.google.gson.annotations.SerializedName; 

public class Headers { 

@SerializedName("Accept") 
@Expose 
private String accept; 
@SerializedName("Accept-Encoding") 
@Expose 
private String acceptEncoding; 
@SerializedName("Accept-Language") 
@Expose 
private String acceptLanguage; 
@SerializedName("Cookie") 
@Expose 
private String cookie; 
@SerializedName("Host") 
@Expose 
private String host; 
@SerializedName("Referer") 
@Expose 
private String referer; 
@SerializedName("Upgrade-Insecure-Requests") 
@Expose 
private String upgradeInsecureRequests; 
@SerializedName("User-Agent") 
@Expose 
private String userAgent; 

public String getAccept() { 
return accept; 
} 

public void setAccept(String accept) { 
this.accept = accept; 
} 

public String getAcceptEncoding() { 
return acceptEncoding; 
} 

public void setAcceptEncoding(String acceptEncoding) { 
this.acceptEncoding = acceptEncoding; 
} 

public String getAcceptLanguage() { 
return acceptLanguage; 
} 

public void setAcceptLanguage(String acceptLanguage) { 
this.acceptLanguage = acceptLanguage; 
} 

public String getCookie() { 
return cookie; 
} 

public void setCookie(String cookie) { 
this.cookie = cookie; 
} 

public String getHost() { 
return host; 
} 

public void setHost(String host) { 
this.host = host; 
} 

public String getReferer() { 
return referer; 
} 

public void setReferer(String referer) { 
this.referer = referer; 
} 

public String getUpgradeInsecureRequests() { 
return upgradeInsecureRequests; 
} 

public void setUpgradeInsecureRequests(String upgradeInsecureRequests) { 
this.upgradeInsecureRequests = upgradeInsecureRequests; 
} 

public String getUserAgent() { 
return userAgent; 
} 

public void setUserAgent(String userAgent) { 
this.userAgent = userAgent; 
} 

}

しかし、私は私のExample.classが適切に満たしていない結果だとき：私はPOJOにJSONに変換するためにhttp://www.jsonschema2pojo.org/を使用それは

{ 
"args": {}, 
"headers": { 
    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,* /*;q=0.8", 
"Accept-Encoding": "gzip, deflate", 
"Accept-Language": "pl,en-US;q=0.7,en;q=0.3", 
"Cookie": "_ga=GA1.2.1591535064.1485716088; _gat=1", 
"Host": "httpbin.org", 
"Referer": "http://httpbin.org/", 
"Upgrade-Insecure-Requests": "1", 
"User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0" 
}, 
"origin": "83.10.45.163", 
"url": "http://httpbin.org/get" 
}

のように見えます。いくつかのヌルフィールドがあります... SSを見てください：