To build this you will need to obtain the following depenencies.  The Bouncy Castle versions may need to be different based on your JDK level.

  bcpg-jdk15-141.jar

  bcprov-jdk15-141.jar

  commons-cli-1.1.jar

Then you can try something like:

  java net.tamas.bcpg.DecryptAndVerifyFile -d test2_secret.asc -p secret -v test1_pub.asc -i test.txt.asc -o verify.txt

And expect to get a verify.txt that's the same as test.txt.  Maybe.

Here’s the download: PgpDecryptAndVerify.zip