Unable to deploy project to heroku?

Question

Java

[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ BenikShop ---
remote:        [INFO] Downloading from central: https://repo.maven.apache.org/maven2/org/slf4j/slf4j-jdk14/1.5.6/slf4j-jdk14-1.5.6.pom
remote:        [INFO] Downloaded from central: https://repo.maven.apache.org/maven2/org/slf4j/slf4j-jdk14/1.5.6/slf4j-jdk14-1.5.6.pom (1.9 kB at 380 kB/s)
remote:        [INFO] Downloading from central: https://repo.maven.apache.org/maven2/org/slf4j/slf4j-parent/1.5.6/slf4j-parent-1.5.6.pom
remote:        [INFO] Downloaded from central: https://repo.maven.apache.org/maven2/org/slf4j/slf4j-parent/1.5.6/slf4j-parent-1.5.6.pom (7.9 kB at 1.6 MB/s)
remote:        [INFO] Downloading from central: https://repo.maven.apache.org/maven2/org/slf4j/slf4j-api/1.5.6/slf4j-api-1.5.6.pom
remote:        [INFO] Downloaded from central: https://repo.maven.apache.org/maven2/org/slf4j/slf4j-api/1.5.6/slf4j-api-1.5.6.pom (3.0 kB at 597 kB/s)
remote:        [INFO] Downloading from central: https://repo.maven.apache.org/maven2/org/slf4j/jcl-over-slf4j/1.5.6/jcl-over-slf4j-1.5.6.pom
remote:        [INFO] Downloaded from central: https://repo.maven.apache.org/maven2/org/slf4j/jcl-over-slf4j/1.5.6/jcl-over-slf4j-1.5.6.pom (2.2 kB at 434 kB/s)
remote:        [INFO] Downloading from central: https://repo.maven.apache.org/maven2/com/thoughtworks/qdox/qdox/2.0-M9/qdox-2.0-M9.pom
remote:        [INFO] Downloaded from central: https://repo.maven.apache.org/maven2/com/thoughtworks/qdox/qdox/2.0-M9/qdox-2.0-M9.pom (16 kB at 2.3 MB/s)
remote:        [INFO] Downloading from central: https://repo.maven.apache.org/maven2/com/thoughtworks/qdox/qdox/2.0-M9/qdox-2.0-M9.jar
remote:        [INFO] Downloaded from central: https://repo.maven.apache.org/maven2/com/thoughtworks/qdox/qdox/2.0-M9/qdox-2.0-M9.jar (317 kB at 21 MB/s)
remote:        [INFO] Changes detected - recompiling the module!
remote:        [INFO] Compiling 7 source files to /tmp/build_752c9fc3/target/classes
remote:        [INFO] ------------------------------------------------------------------------
remote:        [INFO] BUILD FAILURE
remote:        [INFO] ------------------------------------------------------------------------
remote:        [INFO] Total time:  10.037 s
remote:        [INFO] Finished at: 2022-01-28T14:04:17Z
remote:        [INFO] ------------------------------------------------------------------------
remote:        [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project BenikShop: Fatal error compiling: invalid target release: 11 -> [Help 1]
remote:        [ERROR]
remote:        [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
remote:        [ERROR] Re-run Maven using the -X switch to enable full debug logging.
remote:        [ERROR]
remote:        [ERROR] For more information about the errors and possible solutions, please read the following articles:
remote:        [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
remote:
remote:  !     ERROR: Failed to build app with Maven
remote:        We're sorry this build is failing! If you can't find the issue in application code,
remote:        please submit a ticket so we can help: https://help.heroku.com/
remote:
remote:  !     Push rejected, failed to compile Java app.
remote:
remote:  !     Push failed
remote: Verifying deploy...
remote:
remote: !       Push rejected to frebitest1.
remote:
To https://git.heroku.com/frebitest1.git
 ! [remote rejected] main -> main (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/frebitest1.git'

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.6.3</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.elfbar</groupId>
  <artifactId>BenikShop</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>BenikShop</name>
  <description>Demo project for Spring Boot</description>
  <properties>
    <java.version>11</java.version>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-compiler-plugin</artifactId>
      <version>3.8.1</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <scope>runtime</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <scope>runtime</scope>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.security</groupId>
      <artifactId>spring-security-test</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>11</source>
          <target>11</target>
        </configuration>
      </plugin>
    </plugins>
  </build>


</project>

Answer 1

Good afternoon. I'll supplement Dmitry Roo
's answer . It says that OpenJDK 8 is used by default https://devcenter.heroku.com/articles/java-support...

Heroku currently uses OpenJDK 8 to run your application by default.

Heroku currently uses OpenJDK 8 to run your application by default. OpenJDK versions 17, 15, 13, 11, and 7 are also available. Depending on the major version you select the latest available update of that JDK will be used each time you deploy your app.

Current default versions are:

    Java 7 - 1.7.0_332
    Java 8 - 1.8.0_322
    Java 11 - 11.0.14
    Java 13 - 13.0.10
    Java 15 - 15.0.6
    Java 17 - 17.0.2

Read the Specifying a Java version chapter from the link above to understand how to change the version.

Answer 2

Fatal error compiling: invalid target release: 11
Apparently the java version is less than 11