title: minifyEnabled true generating many warnings
body: <p>Hi all after changing build.gradle properties <code>minifyEnabled true</code>  I am getting following error. I read that If we use <code>minifyEnabled true</code> then</p>
  
  <pre><code>The ProGuard tool shrinks, optimizes, and obfuscates your code by removing unused code and renaming classes, fields, and methods with semantically obscure names. The result is a smaller sized .apk file that is more difficult to reverse engineer
  </code></pre>
  
  <p>I want to use above benifits. </p>
  
  <pre><code>Warning:butterknife.internal.ButterKnifeProcessor: can't find superclass or     interface javax.annotation.processing.AbstractProcessor
  Warning:retrofit.RxSupport$1: can't find superclass or interface rx.Observable$OnSubscribe
  Warning:library class dagger.internal.codegen.GraphAnalysisErrorHandler extends or implements program class dagger.internal.Linker$ErrorHandler
  Warning:library class dagger.internal.codegen.GraphAnalysisInjectBinding extends or implements program class dagger.internal.Binding
  Warning:library class dagger.internal.codegen.GraphAnalysisLoader extends or implements program class dagger.internal.Loader
  Warning:library class dagger.internal.codegen.GraphAnalysisProcessor$1 extends or implements program class dagger.internal.BindingsGroup
  Warning:library class dagger.internal.codegen.GraphAnalysisProcessor$2 extends or implements program class dagger.internal.BindingsGroup
  Warning:library class dagger.internal.codegen.GraphAnalysisProcessor$ProviderMethodBinding extends or implements program class dagger.internal.ProvidesBinding
  Warning:library class dagger.internal.codegen.GraphAnalysisStaticInjection extends or implements program class dagger.internal.StaticInjection
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.AbstractProcessor
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced cla ss javax.annotation.processing.ProcessingEnvironment
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.Filer
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.tools.JavaFileObject
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Modifier
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.ElementKind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeVariable
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.util.Types
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeKind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.ArrayType
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.DeclaredType
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.ExecutableElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.ElementKind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.ExecutableElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.VariableElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.DeclaredType
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeKind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.SourceVersion
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced field 'javax.annotation.processing.ProcessingEnvironment processingEnv' in program class butterknife.internal.ButterKnifeProcessor
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.ProcessingEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.tools.Diagnostic$Kind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.Messager
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.util.Elements
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.PackageElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.AbstractProcessor
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.DeclaredType
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.ExecutableElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.VariableElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.ProcessingEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.Filer
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.tools.JavaFileObject
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Modifier
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.ElementKind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.util.Types
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeKind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.SourceVersion
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.tools.Diagnostic$Kind
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.Messager
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.util.Elements
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.PackageElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.tools.Diagnostic
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.util.Elements
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.util.Types
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.Filer
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.ProcessingEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.tools.JavaFileObject
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Modifier
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeVariable
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.ArrayType
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.DeclaredType
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeVariable
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
  Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.annotation.processing.RoundEnvironment
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeVariable
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.VariableElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.ExecutableElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.VariableElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.DeclaredType
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.type.TypeMirror
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.SourceVersion
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.Element
   Warning:butterknife.internal.ButterKnifeProcessor: can't find referenced class javax.lang.model.element.TypeElement
   Warning:com.fasterxml.jackson.databind.ext.DOMSerializer: can't find referenced class org.w3c.dom.bootstrap.DOMImplementationRegistry
   Warning:com.squareup.okhttp.internal.huc.HttpsURLConnectionImpl: can't find referenced method 'long getContentLengthLong()' in program class com.squareup.okhttp.internal.huc.HttpURLConnectionImpl
     Warning:com.squareup.okhttp.internal.huc.HttpsURLConnectionImpl: can't find referenced method 'long getHeaderFieldLong(java.lang.String,long)' in program class com.squareup.okhttp.internal.huc.HttpURLConnectionImpl    
  
  
  (http://proguard.sourceforge.net/manual/troubleshooting.html#dependency)
     Warning:there were 5 unresolved references to program class members.
       Your input classes appear to be inconsistent.
       You may need to recompile the code.
                 (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedprogramclassmember)
   :app:proguardRelease FAILED
    Error:Execution failed for task ':app:proguardRelease'.
   &gt; java.io.IOException: Please correct the above warnings first.
   Information:BUILD FAILED
  Information:Total time: 13.828 secs
   Information:1 error
  Information:201 warnings
  Information:See complete output in console
  </code></pre>
  
  <p>How to resolve this issue. Any suggestion will be appreciated. Thanks in advance.</p>