Error MSB6006: "java.exe" exited with code 1 when ProGuard enabled - xamarin

Question

I try to resolve this issue last few days, still without success.
If I build release version without proguard then everything is OK.
I read many topics about possible problems but nothing help in my case.
So far I did as follow:
Java max heap size - 1G
Use "mklink" - mklink /j C:\android-sdk “C:\Program Files (x86)\Android\android-sdk”
Created own proguard.cfg with content:
General Android
-dontwarn org.apache.http.**
-dontwarn android.net.http.AndroidHttpClient
Android Support Library
-keep class android.support.multidex.MultiDexApplication
-keep class android.support.v4.**
-keep class android.support.v7.** {
public *; }
Google Play Billing
-keep class com.android.vending.billing.**
Google Play Services
-dontwarn com.google.android.gms.internal.*
-keep class * extends java.util.ListResourceBundle {
protected java.lang.Object[][] getContents(); }
Manually update ProGuard to latest version.
And the result is 0 warnings and 1 error.
ERROR:
C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(1929,3):
error MSB6006: "java.exe" exited with code 1.
What else can I do?
Please help.
Update.
I created brand new app "Xamarin Hello World" and there "ProGuard" works. So it must be something wrong with my app not a system.
But visual studio doesn't show me any other error apart that Java code 1. So how to track where is a problem?
UPDATE
The problem was in my "proguard.cfg" file. I copy content from other source and one line there should be comment but it wasn't. So this problem gone. But now some warnings come out:
2>PROGUARD : warning : can't write resource [META-INF/MANIFEST.MF](Duplicate zip entry [classes.jar:META-INF/MANIFEST.MF])
2>Copying resources from program jar [G:\ApkiC-Sharp\GNote\GNote\GNote.Android\obj\Release\__library_projects__\Xamarin.GooglePlayServices.Basement\library_project_imports\classes.jar](TaskId:345)
2>PROGUARD : warning : can't write resource [META-INF/MANIFEST.MF] (Duplicate zip entry [classes.jar:META-INF/MANIFEST.MF])
2>Copying resources from program jar [G:\ApkiC-Sharp\GNote\GNote\GNote.Android\obj\Release\__library_projects__\Xamarin.GooglePlayServices.Maps\library_project_imports\classes.jar] (TaskId:345)
2>PROGUARD : warning : can't write resource [META-INF/MANIFEST.MF] (Duplicate zip entry [classes.jar:META-INF/MANIFEST.MF])
2>Copying resources from program jar [G:\ApkiC-Sharp\GNote\GNote\GNote.Android\obj\Release\__library_projects__\Xamarin.GooglePlayServices.Tasks\library_project_imports\classes.jar] (TaskId:345)
2>PROGUARD : warning : can't write resource [META-INF/MANIFEST.MF] (Duplicate zip entry [classes.jar:META-INF/MANIFEST.MF])
What dose it mean? Is it something to worried about?
How to check if "ProGuard" works fine?

Answer 1

I was also facing the same issue on my Windows 10 x64 and visual studio 2015. I have set the JDK path to JDK 1.8 under android settings in Visual studio tools ->options ->xamarin ->java development kit location. it was pointing to "C:\Program Files (x86)\Java\jdk1.7.0_55" and I made it to "C:\Program Files\Java\jdk1.8.0_31", and issue has been fixed.

Answer 2

Try enabling the Multi-Dex compilation option.