Adding maven-publish plugin to build.gradle

build.gradle

apply plugin:"maven-publish"

// Other closure blocks

publishing {
    publications {
        maven(MavenPublication) {
            from components.java
        }
    }
    repositories {
        maven {
            credentials {
                username NEXUS_USERNAME
                password NEXUS_PASSWORD
            }
            url "https://[my.nexus.repo]/repository/releases/"
        }
    }
}

NEXUS_USERNAME and NEXUS_PASSWORD are command line parameters for the gradle task. You might use it in a build server like:

./gradlew -PNEXUS_USERNAME=[your_username] -PNEXUS_PASSWORD=[your_password] publish