Custom Error Handling with Retrofit when obfuscated using proguard gives java.lang.reflect.UndeclaredThrowableException

Question

Have written custom error handling for retrofit. The code works perfectly when minifyEnabled false. When I enable proguard, I get the following exception

12-17 10:14:07.688  18568-19041/com.mobility.cariq.carscore W/System.err﹕ java.lang.reflect.UndeclaredThrowableException
12-17 10:14:07.688  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at $Proxy9.updatesForModel(Native Method)
12-17 10:14:07.688  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at com.mobility.cariq.carscore.rest.service.UpdateDatabaseService.jiijijliillliliilllil(UpdateDatabaseService.java:119)
12-17 10:14:07.688  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at com.mobility.cariq.carscore.rest.service.UpdateDatabaseService.onHandleIntent(UpdateDatabaseService.java:75)
12-17 10:14:07.689  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
12-17 10:14:07.689  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:102)
12-17 10:14:07.689  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at android.os.Looper.loop(Looper.java:136)
12-17 10:14:07.689  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at android.os.HandlerThread.run(HandlerThread.java:61)
12-17 10:14:07.689  18568-19041/com.mobility.cariq.carscore W/System.err﹕ Caused by: com.mobility.cariq.carscore.rest.error.UnauthorizedException
12-17 10:14:07.690  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at com.mobility.cariq.carscore.rest.error.RestErrorHandler.handleError(RestErrorHandler.java:40)
12-17 10:14:07.690  18568-19041/com.mobility.cariq.carscore W/System.err﹕ at retrofit.RestAdapter$RestHandler.invoke(RestAdapter.java:242)

Error Handler

public class RestErrorHandler implements ErrorHandler {

@Override
public Throwable handleError(RetrofitError cause) {
    Response r = cause.getResponse();

    if (r != null && r.getStatus() == 400) {

        try {
            RestError mRestError = (RestError) cause.getBodyAs(RestError.class);
            final String exception = mRestError.getMessages().get(0);
            return new UnauthorizedException(exception);
        } catch (Exception e) {
            e.printStackTrace();
            LogUtility.NoteLog(e);
        }
    }
    return cause;
}

Proguard

-obfuscationdictionary keywords.txt
-classobfuscationdictionary keywords.txt
-packageobfuscationdictionary keywords.txt

-dontwarn android.telephony.**
-keepattributes SourceFile,LineNumberTable

-dontwarn butterknife.internal.**
-keep class **$$ViewInjector { *; }
-keepnames class * { @butterknife.InjectView *;}

-keepattributes Signature
-keepattributes *Annotation*
-keep class com.squareup.okhttp.** { *; }
-keep interface com.squareup.okhttp.** { *; }
-dontwarn com.squareup.okhttp.**

-dontwarn rx.**
-dontwarn retrofit.**
-keep class retrofit.** { *; }
-keepclasseswithmembers class * {
    @retrofit.http.* <methods>;
}

-keep class sun.misc.Unsafe { *; }
-keep class com.mobility.cariq.carscore.rest.model.** { *; }
-keep class com.mobility.cariq.carscore.rest.error.** { *; }
-dontwarn java.nio.file.**
-dontwarn org.codehaus.mojo.**

-dontwarn org.joda.convert.**

I am fairly new to using proguard and retrofit. I am unable to understand, how to handle the exception.

Answer 1

Proguard removes Exception attributes by default.

-keepattributes Exceptions will make sure that your Throwable remains in your code after obfuscation.

Answer 2

Looks like UnauthorizedException is a checked exception (extends from Exception, not RuntimeException) which means you need to declare a throws clause on all of your service interfaces.

interface MyService {
  @GET("/")
  Something doSomething() throws UnauthorizedException;
}