I ran into the same problem. I had a PNG file in a Java package and it wasn't exported in the final JAR along with the sources, which caused the app to crash upon start (file not found).
None of the answers above solved my problem but I found the solution on the Gradle forums. I added the following to my build.gradle
file :
sourceSets.main.resources.srcDirs = [ "src/" ]
sourceSets.main.resources.includes = [ "**/*.png" ]
It tells Gradle to look for resources in the src
folder, and ask it to include only PNG files.
EDIT: Beware that if you're using Eclipse, this will break your run configurations and you'll get a main class not found
error when trying to run your program. To fix that, the only solution I've found is to move the image(s) to another directory, res/
for example, and to set it as srcDirs
instead of src/
.