Error:Execution failed for task ':app:packageRelease'.> Unable to compute hash of ..\app\build\intermediates\classes-proguard\..\release\classes.jar

Question

I am getting the following error message when I enable Proguard from gradle file and to generate an release build file.

Exception while processing task java.io.IOException: proguard.ParseException: Expecting type and name instead of just '' before '(' in line 169 of file 'S:\workspace\Projects..\app\build\intermediates\proguard-rules..\release\aapt_rules.txt' at com.android.build.gradle.tasks.AndroidProGuardTask$1.run(AndroidProGuardTask.java:117) at com.android.builder.tasks.Job.runTask(Job.java:48) at com.android.build.gradle.tasks.SimpleWorkQueue$EmptyThreadContext.runTask(SimpleWorkQueue.java:41) at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:227) at java.lang.Thread.run(Thread.java:745) Error:proguard.ParseException: Expecting type and name instead of just '' before '(' in line 169 of file 'S:\workspace\Projects..\app\build\intermediates\proguard-rules..\release\aapt_rules.txt' at proguard.ConfigurationParser.parseMemberSpecificationArguments(ConfigurationParser.java:908) at proguard.ConfigurationParser.parseClassSpecificationArguments(ConfigurationParser.java:748) at proguard.ConfigurationParser.parseKeepClassSpecificationArguments(ConfigurationParser.java:534) at proguard.ConfigurationParser.parse(ConfigurationParser.java:165) at proguard.gradle.ProGuardTask.getConfiguration(ProGuardTask.java:1142) at proguard.gradle.ProGuardTask.proguard(ProGuardTask.java:1074) at com.android.build.gradle.tasks.AndroidProGuardTask.doMinification(AndroidProGuardTask.java:139) at com.android.build.gradle.tasks.AndroidProGuardTask$1.run(AndroidProGuardTask.java:115) ... 4 more Error:Execution failed for task ':app:packageProRelease'. > Unable to compute hash of S:\workspace\Projects\app\build\intermediates\classes-proguard\Pro\release\classes.jar

I am using following libraries in the code:

1. AndroidScanLib.jar
2. apache-mime4j-core-0.7.jar
3. httpclient-4.1.2.jar
4. httpmime-4.2.3.jar
5. libGoogleAnalyticsServices.jar
6. MobileImagingEngine.jar
7. MobileImagingEngine_Doc.jar
8. SmartScan.jar
9. sqlcipher.jar

Answer 1

A weird workaround: disable minifyEnabled (minifyEnabled false), generate signed APK, and then re-enable it (minifyEnabled true) and generate the signed APK again. Hope this works.

Answer 2

In my case i was using a custom library that i created and i had set minifyEnabled true, and in the dependent module i again did same minifyEnabled true. keeping this at only one place solved my problem. Same can be case with libraries other than your own!