Error with running a command in Gradle ./gradlew gem

I run this command and get this error message

[root@Daley-DB grpc-plugin]# ./gradlew gem
To honour the JVM settings for this build a single-use Daemon process will be forked. See The Gradle Daemon.
Daemon will be stopped at the end of the build

FAILURE: Build failed with an exception.

• What went wrong:
  Task ‘gem’ not found in root project ‘logstash’.

• Try:
  Run gradlew tasks to get a list of available tasks. Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

• Get more help at https://help.gradle.org

BUILD FAILED in 38s