Not able to resolve java.lang.NoSuchMethodError with GSON library

Question

I was trying to build a sample Retrofit Java program taken from;

https://github.com/square/retrofit/blob/master/samples/src/main/java/com/example/retrofit/SimpleService.java

I included required dependent jars (retrofit-2.0.0.jar,converter-gson-2.0.0.jar,okhttp-3.0.0-RC1.jar,okio-1.6.0.jar and gson-2.0.jar) to the build path.

I encounter the following exception while trying to run the application.

Exception in thread "main" java.lang.NoSuchMethodError: com.google.gson.Gson.getAdapter(Lcom/google/gson/reflect/TypeToken;)Lcom/google/gson/TypeAdapter;
at retrofit2.converter.gson.GsonConverterFactory.responseBodyConverter(GsonConverterFactory.java:63)
at retrofit2.Retrofit.nextResponseBodyConverter(Retrofit.java:325)
at retrofit2.Retrofit.responseBodyConverter(Retrofit.java:308)
at retrofit2.ServiceMethod$Builder.createResponseConverter(ServiceMethod.java:651)
at retrofit2.ServiceMethod$Builder.build(ServiceMethod.java:166)
at retrofit2.Retrofit.loadServiceMethod(Retrofit.java:166)
at retrofit2.Retrofit$1.invoke(Retrofit.java:145)
at com.sun.proxy.$Proxy0.contributors(Unknown Source)
at SimpleService.main(SimpleService.java:40)

Am I missing any dependent jar?

I am trying to use Retrofit in standalone Java application and was testing samples to get used to it. It will be great if someone could point me to a simple sample program that demonstrates the working of Retrofit, even a sample of earlier version would be good.

Answer 1

try to add this in gradle:

compile 'com.google.code.gson:gson:2.6.2'

it works well for me :)

Answer 2

Here are some dependencies that might help you.

GSON and Retrofit

compile 'com.google.code.gson:gson:2.7'
compile 'com.squareup.retrofit2:converter-gson:2.1.0'
compile 'com.squareup.retrofit2:retrofit:2.1.0'

HTTP

compile 'org.apache.commons:commons-lang3:3.4'
compile 'org.apache.httpcomponents:httpcore:4.4.5'

Try to clean your project and sync with gradle. Or try using the same version jar files in your project.

Or have you replaced this line with correct value.

@GET("/repos/{owner}/{repo}/contributors")

What is the response after calling the API. plz check the URL in the browser.

let me know if issue still persists.