call library functions in jenkinsfile

Jenkinsfile

@@ -1,7 +1,10 @@
+#!/usr/bin/env groovy
+
+@Library('jenkins-shared-library')
 def gv
 
 pipeline {
-    agent any
+    agent none
     tools {
         maven 'Maven'
     }
@@ -15,16 +18,12 @@ pipeline {
         }
         stage("build jar") {
             steps {
-                script {
+                buildJar()
-                    gv.buildJar()
-                }
             }
         }
         stage("build image") {
             steps {
-                script {
+                buildImage()
-                    gv.buildImage()
-                }
             }
         }
         stage("deploy") {

script.groovy

@@ -1,17 +1,3 @@
-def buildJar() {
-    echo "building the application..."
-    sh 'mvn package'
-} 
-
-def buildImage() {
-    echo "building the docker image..."
-    withCredentials([usernamePassword(credentialsId: 'docker-hub-repo', passwordVariable: 'PASS', usernameVariable: 'USER')]) {
-        sh 'docker build -t nanajanashia/demo-app:jma-2.0 .'
-        sh "echo $PASS | docker login -u $USER --password-stdin"
-        sh 'docker push nanajanashia/demo-app:jma-2.0'
-    }
-} 
-
 def deployApp() {
     echo 'deploying the application...'
 }