title: Android proguard Gson Error
body: <p>An error occurred while trying to make the app as a release.
  Errors are likely to continue in the coming Gson.
  While retrofit guard as professional use official
  But because of what I do not know why.</p>
  
  <p>These libraries are currently in use.</p>
  
  <pre><code>dependencies {
  compile fileTree(include: ['*.jar'], dir: 'libs')
  apt 'com.jakewharton:butterknife-compiler:8.4.0'
  compile 'com.jakewharton:butterknife:8.4.0'
  compile 'com.android.support:support-v4:24.1.1'
  compile 'com.android.support:support-annotations:24.1.1'
  compile 'com.android.support:appcompat-v7:24.1.1'
  compile 'com.android.support:design:24.1.1'
  compile 'io.reactivex:rxandroid:1.2.1'
  compile 'com.trello:rxlifecycle:0.6.1'
  compile 'com.trello:rxlifecycle-components:0.6.1'
  compile 'com.squareup.retrofit2:retrofit:2.1.0'
  compile 'com.squareup.retrofit2:converter-gson:2.1.0'
  compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'
  compile 'com.squareup.okhttp3:okhttp:3.3.1'
  compile 'com.squareup.okhttp3:okhttp-urlconnection:3.3.1'
  compile 'com.squareup.okhttp3:logging-interceptor:3.3.1'
  compile 'com.github.bumptech.glide:glide:3.7.0'
  compile 'jp.wasabeef:glide-transformations:2.0.1'
  compile 'com.github.captain-miao:autofittextview:0.2.2'
  compile 'com.artemzin.rxjava:proguard-rules:1.1.9.0'
  </code></pre>
  
  <p>and ProGuard also being used as follows:</p>
  
  <pre><code>-libraryjars libs
  -keepattributes SourceFile,LineNumberTable
  -dontwarn okio.**
  -dontnote retrofit2.Platform
  -dontnote retrofit2.Platform$IOS$MainThreadExecutor
  -dontwarn retrofit2.Platform$Java8
  -keepattributes Signature
  -keepattributes Exceptions
  -keepattributes Signature
  -keepattributes *Annotation*
  -keep class sun.misc.Unsafe { *; }
  -keep class com.google.gson.examples.android.model.** { *; }
  -keep class com.google.gson.** { *; }
  </code></pre>
  
  <p>apk is made well. However, if you run the following error occurs.</p>
  
  <pre><code>STACK_TRACE=java.lang.AssertionError: java.lang.NoSuchFieldException: OPTION
  at com.google.gson.internal.bind.TypeAdapters$EnumTypeAdapter.&lt;init&gt;       (TypeAdapters.java:808)
  at com.google.gson.internal.bind.TypeAdapters$30.create(TypeAdapters.java:834)
  at com.google.gson.Gson.getAdapter(Gson.java:423)
  at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:115)
  at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:164)
  at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:100)
  at com.google.gson.Gson.getAdapter(Gson.java:423)
  at d.b.a.a.a(GsonConverterFactory.java:63)
  at d.at.a(Retrofit.java:325)
  at d.at.b(Retrofit.java:308)
  at d.ax.c(ServiceMethod.java:704)
  at d.ax.a(ServiceMethod.java:167)
  at d.at.a(Retrofit.java:166)
  at d.au.invoke(Retrofit.java:145)
  at java.lang.reflect.Proxy.invoke(Proxy.java:393)
  at $Proxy2.b(Unknown Source)
  </code></pre>
  
  <p>Retro -fit are using this.</p>
  
  <pre><code>            net = new Retrofit.Builder()
                  .baseUrl(SERVER_URL)
                  .addConverterFactory(GsonConverterFactory.create()) //Json Parser
                  .addCallAdapterFactory(RxJavaCallAdapterFactory.create()) //Rxandroid
                  .client(client)
                  .build()
                  .create(xxx.class);
  </code></pre>