Spring boot gradle project deployed to heroku using bitbucket pipeline gives error no main manifest attribute, in build/libs/app-SNAPSHOT-plain.jar

Question

I have a Spring boot gradle project built using IntelliJIDEA with gradle.build:

plugins {
    id 'org.springframework.boot' version '2.5.5'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}

group = 'pk.inlab.app.web'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.springframework.boot:spring-boot-starter-mail'
    implementation 'org.springframework.boot:spring-boot-starter-security'
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-hateoas'
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'

    // Apache commons
    implementation 'commons-beanutils:commons-beanutils:1.9.4'
  
    // Jwt
    implementation 'io.jsonwebtoken:jjwt:0.9.1'

    // OpenAPI and Swagger
    implementation 'org.springdoc:springdoc-openapi-ui:1.5.11'
    implementation 'org.springdoc:springdoc-openapi-data-rest:1.5.11'

    // Passy
    implementation 'org.passay:passay:1.6.1'

    // Thymeleaf for registration email with template
    implementation 'org.thymeleaf:thymeleaf-spring5'


    compileOnly 'org.projectlombok:lombok'
    runtimeOnly 'org.postgresql:postgresql'

    annotationProcessor 'org.projectlombok:lombok'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    testImplementation 'org.springframework.security:spring-security-test'
    // Rest Assured
    testImplementation 'io.rest-assured:spring-mock-mvc:4.4.0'
    // hamcrest-library
    testImplementation 'org.hamcrest:hamcrest-library:2.2'

}

test {
    useJUnitPlatform()
}

the project works well on local machine, when pushed to bitbucket with pipeline setting file bitbucket-pipelines.yml:

#  Template Java Gradle build

#  This template allows you to test and build your Java project with Gradle.
#  The workflow allows running tests, code checkstyle and security scans on the default branch.

# Prerequisites: appropriate project structure should exist in the repository.

image: gradle:7.2

pipelines:
  default:
    - parallel:
      - step:
          name: Build and Test
          caches:
            - gradle
          script:
            - gradle clean build
            - git archive --format=tar.gz master -o application.tar.gz 
            - pipe: atlassian/heroku-deploy:1.2.1
              variables:
                HEROKU_API_KEY: $HEROKU_API_KEY
                HEROKU_APP_NAME: $HEROKU_APP_NAME
                ZIP_FILE : "application.tar.gz"
          after-script:
            - pipe: atlassian/checkstyle-report:0.2.0
      - step:
          name: Security Scan
          script:
            # Run a security scan for sensitive data.
            # See more security tools at https://bitbucket.org/product/features/pipelines/integrations?&category=security
            - pipe: atlassian/git-secrets-scan:0.4.3

the build logs are all correct, it shows:

-----> Building on the Heroku-20 stack
-----> Using buildpack: heroku/gradle
-----> Gradle app detected
-----> Spring Boot detected
-----> Installing JDK 1.8... done
-----> Building Gradle app...
-----> executing ./gradlew build -x check
       To honour the JVM settings for this build a single-use Daemon process will be forked. See https://docs.gradle.org/7.2/userguide/gradle_daemon.html#sec:disabling_the_daemon.
       Daemon will be stopped at the end of the build 
       > Task :compileJava
       > Task :processResources
       > Task :classes
       > Task :bootJarMainClassName
       > Task :bootJar
       > Task :jar
       > Task :assemble
       > Task :build
       
       BUILD SUCCESSFUL in 20s
       5 actionable tasks: 5 executed
-----> Discovering process types
       Procfile declares types     -> (none)
       Default types for buildpack -> web
-----> Compressing...
       Done: 99.4M
-----> Launching...
       Released v8
       https://rest-todo-work.herokuapp.com/ deployed to Heroku

after all when I visit the site its shows:

when I check heroku logs it shows:

2021-10-26T04:35:07.000000+00:00 app[api]: Build started by user [email protected]
2021-10-26T04:35:46.654664+00:00 app[api]: Release v8 created by user [email protected]
2021-10-26T04:35:46.654664+00:00 app[api]: Deploy cf272d57 by user [email protected]
2021-10-26T04:35:46.918113+00:00 heroku[web.1]: State changed from crashed to starting
2021-10-26T04:35:50.193127+00:00 heroku[web.1]: Starting process with command `java -Dserver.port=37836 $JAVA_OPTS -jar build/libs/*.jar`
2021-10-26T04:35:50.877195+00:00 app[web.1]: Create a Procfile to customize the command used to run this process: https://devcenter.heroku.com/articles/procfile
2021-10-26T04:35:50.890431+00:00 app[web.1]: Setting JAVA_TOOL_OPTIONS defaults based on dyno size. Custom settings will override them.
2021-10-26T04:35:50.894017+00:00 app[web.1]: Picked up JAVA_TOOL_OPTIONS: -Xmx300m -Xss512k -XX:CICompilerCount=2 -Dfile.encoding=UTF-8
2021-10-26T04:35:50.954182+00:00 app[web.1]: no main manifest attribute, in build/libs/to-do-0.0.1-SNAPSHOT-plain.jar
2021-10-26T04:35:51.082759+00:00 heroku[web.1]: Process exited with status 1
2021-10-26T04:35:51.148321+00:00 heroku[web.1]: State changed from starting to crashed
2021-10-26T04:36:03.000000+00:00 app[api]: Build succeeded
2021-10-26T04:39:01.736780+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=rest-todo-work.herokuapp.com request_id=21a8013c-0771-4758-8245-a575145bc3b0 fwd="111.119.183.2" dyno= connect= service= status=503 bytes= protocol=https
2021-10-26T04:39:02.249498+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=rest-todo-work.herokuapp.com request_id=7fd63420-a032-49ef-bd81-990df93bc5d1 fwd="111.119.183.2" dyno= connect= service= status=503 bytes= protocol=https

all right when I wanted to solve no main manifest attribute, I found a SO post which suggests to add:

jar {
    manifest {
        attributes 'Main-Class': 'pk.inlab.app.web.todo.ToDoApplication'
    }
}

in gradle file, I added and heroku logs are:

2021-10-26T04:28:04.396482+00:00 heroku[web.1]: State changed from crashed to starting
2021-10-26T04:28:07.756486+00:00 heroku[web.1]: Starting process with command `java -Dserver.port=45162 $JAVA_OPTS -jar build/libs/*.jar`
2021-10-26T04:28:09.250355+00:00 app[web.1]: Create a Procfile to customize the command used to run this process: https://devcenter.heroku.com/articles/procfile
2021-10-26T04:28:09.274928+00:00 app[web.1]: Setting JAVA_TOOL_OPTIONS defaults based on dyno size. Custom settings will override them.
2021-10-26T04:28:09.278725+00:00 app[web.1]: Picked up JAVA_TOOL_OPTIONS: -Xmx300m -Xss512k -XX:CICompilerCount=2 -Dfile.encoding=UTF-8
2021-10-26T04:28:09.420855+00:00 app[web.1]: Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
2021-10-26T04:28:09.420930+00:00 app[web.1]: at pk.inlab.app.web.todo.ToDoApplication.main(ToDoApplication.java:12)
2021-10-26T04:28:09.420987+00:00 app[web.1]: Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
2021-10-26T04:28:09.421018+00:00 app[web.1]: at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
2021-10-26T04:28:09.421046+00:00 app[web.1]: at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
2021-10-26T04:28:09.421075+00:00 app[web.1]: at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
2021-10-26T04:28:09.421102+00:00 app[web.1]: at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
2021-10-26T04:28:09.421129+00:00 app[web.1]: ... 1 more
2021-10-26T04:28:09.609559+00:00 heroku[web.1]: Process exited with status 1

this adds a new error. Any suggestions for these issues.

Answer 1

I was facing the same issue and tried to search a legit solution, in the end I found that, all you have to do is to add :

bootJar {
    archiveClassifier.set('boot')
}

jar {
    archiveClassifier.set('')
}

and let the gradle handle all other things, let me paste contents of gradle.build file which worked:

plugins {
    id 'org.springframework.boot' version '2.5.5'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}

group = 'pk.inlab.app.web'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.springframework.boot:spring-boot-starter-mail'
    implementation 'org.springframework.boot:spring-boot-starter-security'
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-hateoas'
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'

    // Apache commons
    implementation 'commons-beanutils:commons-beanutils:1.9.4'
    // implementation 'org.apache.commons:commons-collections4:4.4'


    // Jwt
    implementation 'io.jsonwebtoken:jjwt:0.9.1'

    // OpenAPI and Swagger
    implementation 'org.springdoc:springdoc-openapi-ui:1.5.11'
    implementation 'org.springdoc:springdoc-openapi-data-rest:1.5.11'

    // Passy
    implementation 'org.passay:passay:1.6.1'

    // Thymeleaf for registration email with template
    implementation 'org.thymeleaf:thymeleaf-spring5'


    compileOnly 'org.projectlombok:lombok'
    runtimeOnly 'org.postgresql:postgresql'

    annotationProcessor 'org.projectlombok:lombok'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    testImplementation 'org.springframework.security:spring-security-test'
    // Rest Assured
    testImplementation 'io.rest-assured:spring-mock-mvc:4.4.0'
    // hamcrest-library
    testImplementation 'org.hamcrest:hamcrest-library:2.2'

}

// Add these START
bootJar {
    archiveClassifier.set('boot')
}

jar {
    archiveClassifier.set('')
}    
// Add these END 

test {
    useJUnitPlatform()
}

It was the solution which worked for me, hope will work for you as well.

Answer 2

It seems you're deploying/starting the wrong jar file.

2021-10-26T04:35:50.954182+00:00 app[web.1]: no main manifest attribute, in build/libs/to-do-0.0.1-SNAPSHOT-plain.jar

The Spring Boot Gradle plugin gives you two jar files when executing gradlew build:

1. build/libs/to-do-0.0.1-SNAPSHOT-plain.jar - Created by the default jar task and contains only the compiled sources and resources of the project. Even when adding the Main-Class manifest attribute, dependencies are not present and consequently ClassNotFoundException is raised.
2. build/libs/to-do-0.0.1-SNAPSHOT.jar - Contributed by the bootJar task and, in addition to the regular jar contents, also includes all required dependencies to run the application as in java -jar to-do-0.0.1-SNAPSHOT.jar.

That being said, you must deploy build/libs/to-do-0.0.1-SNAPSHOT.jar rather than the -plain one.

According to the Heroku output (build/libs/*.jar) it may be that both are deployed and started:

Starting process with command java -Dserver.port=37836 $JAVA_OPTS -jar build/libs/*.jar

Without knowing too much about Heroku, you could prevent this from happening by building the bootJar only, e.g. by skipping the jar task in you build pipeline: gradlew clean build -x jar.

Answer 3

The same problem happened to me, as heroku runs the jar with the command java -Dserver.port=$PORT $JAVA_OPTS -jar build/libs/*.jar it for some reason was running the jar with the final SNAPSHOT-plain.jar. what I did was basically remove the generation of the SNAPSHOT-plain.jar, leaving only the executable jar. Using the plugin java:

plugins {
    id("org.springframework.boot") version "2.6.3"
    id("io.spring.dependency-management") version "1.0.11.RELEASE"
    kotlin("jvm") version "1.6.10"
    kotlin("plugin.spring") version "1.6.10"

    id ("java")
}

And putting the task:

tasks.jar {
    enabled = false
}