I am getting this error during generate sign APK. please help me.
see this errors
Information:Gradle tasks [:app:assembleRelease]
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
Warning:com.squareup.okhttp.internal.huc.JavaApiConverter$CacheHttpsURLConnection: can't find referenced method 'long getContentLengthLong()' in program class com.squareup.okhttp.internal.huc.JavaApiConverter$CacheHttpURLConnection
Warning:com.squareup.okhttp.internal.huc.JavaApiConverter$CacheHttpsURLConnection: can't find referenced method 'long getHeaderFieldLong(java.lang.String,long)' in program class com.squareup.okhttp.internal.huc.JavaApiConverter$CacheHttpURLConnection
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced field 'com.squareup.okhttp.CacheControl FORCE_CACHE' in program class com.squareup.okhttp.CacheControl
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced method 'com.squareup.okhttp.Request$Builder cacheControl(com.squareup.okhttp.CacheControl)' in program class com.squareup.okhttp.Request$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl$Builder
Warning:okio.DeflaterSink: can't find referenced class org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
Warning:okio.Okio: can't find referenced class java.nio.file.Files
Warning:okio.Okio: can't find referenced class java.nio.file.Path
Warning:okio.Okio: can't find referenced class java.nio.file.OpenOption
Warning:okio.Okio: can't find referenced class java.nio.file.Path
Warning:okio.Okio: can't find referenced class java.nio.file.OpenOption
Warning:okio.Okio: can't find referenced class org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
Warning:okio.Okio: can't find referenced class java.nio.file.Path
Warning:okio.Okio: can't find referenced class java.nio.file.OpenOption
Warning:okio.Okio: can't find referenced class java.nio.file.Path
Warning:okio.Okio: can't find referenced class java.nio.file.OpenOption
Warning:okio.Okio: can't find referenced class org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
Warning:there were 21 unresolved references to classes or interfaces.
Warning:there were 6 unresolved references to program class members.
Warning:Exception while processing task java.io.IOException: Please correct the above warnings first.
Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'.
> Job failed, see logs for details
Information:BUILD FAILED
Information:Total time: 30.672 secs
Information:1 error
Information:23 warnings
Information:See complete output in console