Android studio 3.0 does not generate signed apk

Since Android Studio 3.0 update, the apk generated will be in

{project-folder}/app/release/app-release.apk

Also 1 more file is generated Output.json which holds the apk generation details.

Sample:

[  
   {  
      "outputType":{  
         "type":"APK"
      },
      "apkInfo":{  
         "type":"MAIN",
         "splits":[  

         ],
         "versionCode":1
      },
      "path":"app-debug.apk",
      "properties":{  
         "packageId":"njscommunity.xxxxx",
         "split":"",
         "minSdkVersion":"19"
      }
   }
]

All depends on Gradle build, so at the end it all depends on Gradle version you build with. i.e. Gradle Android plugin for Android Studio.