Kesalahan: Tidak dapat mengekspor atau mengenkripsi kunci pribadi java.lang.nullpointerexception

Running the below command created App signing preferences for play.google.com 
and can solve the issue

keytool -export -rfc -keystore C:\\Users\\USER_NAME\\key.jks -alias key -file C:\\Users\\USER_NAME\\upload_key_public_certificate.pem
Lokesh003