gradle init --use-defaults --type java-application

The above command will setup a basic gradle project

./gradlew build

To prepare a jar which is executable, you need to setup manifest property in build.gradle to identify what is the main class to execute

jar {
    manifest {
        attributes (
            'Main-Class': 'org.example.Main'
        )
    }
}

The above command can build your project

./gradlew jar

The above command creates a new jar file in build/libs folder

java -jar build/libs/filename.jar

The above command will execute your code

• Try to build a jar and run it directly from cli and see if the okhttp code is working or not just like it is working by running directly from intellij
• instead of okhttp try to integrate retrofit library to make the same http call