I have used Retrofit library for my Android application.I need to set connection timeout as 120 Sec. How can I do ? 

Version:

```
compile 'com.squareup.retrofit2:retrofit:2.1.0'
compile 'com.squareup.retrofit2:converter-gson:2.1.0'
compile 'com.google.code.gson:gson:2.8.0'
compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'

```

OperatingApiClient:

```
    public class OperatingApiClient {
    public static final String BASE_URL = "http://172.16.2.39/";
    private static Retrofit retrofit = null;

    public static Retrofit getClient() {
        if (retrofit==null) {
            retrofit = new Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }
    }

```

TargetFileApiInterface:

```
public interface TargetFileApiInterface {
@GET("NNGOperating/GetTargetFileList")
Call<TargetFileApiResponse> getTargetFileList(@Query("api_key") 
String apiKey);

}

```

TargetFileApiResponse:

```
    public class TargetFileApiResponse {
    @SerializedName("TargetFileList")
    private List<TargetFile> targetfileslist;

    public TargetFileApiResponse(List<TargetFile> targetfileslist) {
        this.targetfileslist = targetfileslist;
    }

    public List<TargetFile> getTargetfileslist() {
        return targetfileslist;
    }

    public void setTargetfileslist(List<TargetFile> targetfileslist) {
        this.targetfileslist = targetfileslist;
    }
    }

```