Trying to make the pipeline work

Dockerfile

@@ -4,6 +4,6 @@ WORKDIR /app
 
 COPY target/spring-petclinic-*.jar /app/spring-petclinic.jar
 
-EXPOSE 8080
+EXPOSE 8081
 
 CMD ["java", "-jar", "spring-petclinic.jar"]

Jenkinsfile

@@ -0,0 +1,84 @@
+pipeline {
+    agent any
+    
+    environment {
+        MAVEN_HOME = tool 'M3' // Assuming your Maven tool in Jenkins is named "M3"
+        DOCKER_REPO_MR = "iancumatei67/mr" // Change to your Docker registry/repository for merge requests
+        DOCKER_REPO_MAIN = "iancumatei67/main" // Change to your Docker registry/repository for main branch
+    }
+    
+    stages {
+        stage('Checkstyle') {
+            steps {
+                script {
+                    // Use Maven for Checkstyle
+                    sh "${MAVEN_HOME}/bin/mvn checkstyle:checkstyle"
+                    archiveArtifacts 'target/checkstyle-result.xml'
+                }
+            }
+        }
+        
+        stage('Test') {
+            steps {
+                script {
+                    // Use Maven for testing
+                    sh "${MAVEN_HOME}/bin/mvn test"
+                }
+            }
+        }
+        
+        stage('Build') {
+            steps {
+                script {
+                    // Use Maven for building without tests
+                    sh "${MAVEN_HOME}/bin/mvn package -DskipTests"
+                }
+            }
+        }
+        
+        stage('Create Docker Image (MR)') {
+            when {
+                expression {
+                    // Execute this stage only for merge requests
+                    return env.CHANGE_ID != null
+                }
+            }
+            steps {
+                script {
+                    // Assuming Dockerfile is at the root of the spring-petclinic repo
+                    def gitCommitShort = sh(script: 'git rev-parse --short HEAD', returnStdout: true).trim()
+                    def dockerImageTag = "${DOCKER_REPO_MR}:${gitCommitShort}"
+
+                    sh "docker build -t ${dockerImageTag} ."
+                    sh "docker push ${dockerImageTag}"
+                }
+            }
+        }
+        
+        stage('Create Docker Image (Main)') {
+            when {
+                expression {
+                    // Execute this stage only for the main branch
+                    return env.BRANCH_NAME == 'main'
+                }
+            }
+            steps {
+                script {
+                    // Assuming Dockerfile is at the root of the spring-petclinic repo
+                    def gitCommitShort = sh(script: 'git rev-parse --short HEAD', returnStdout: true).trim()
+                    def dockerImageTag = "${DOCKER_REPO_MAIN}:${gitCommitShort}"
+
+                    sh "docker build -t ${dockerImageTag} ."
+                    sh "docker push ${dockerImageTag}"
+                }
+            }
+        }
+    }
+    
+    post {
+        always {
+            cleanWs() // Clean workspace after the pipeline execution
+        }
+    }
+}
+