error with putting project on Heroku invalid target release: 11

Question

please, help me I spend already 10 hours to solve this problem, and still can't((( my application run in my computer well, but I can't put it to heroku! This is pom

    <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.0</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>

<properties>
    <java.version>11</java.version>
    <spring-cloud.version>2020.0.0-M6</spring-cloud.version>
</properties>

<dependencies>
    <!-- https://mvnrepository.com/artifact/org.apache.camel/camel-mongodb-gridfs -->
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-mongodb-gridfs</artifactId>
        <version>3.7.0</version>
    </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jcl</artifactId>
        <version>5.2.9.RELEASE</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-logging -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-logging</artifactId>
        <version>2.3.6.RELEASE</version>
    </dependency>


    <dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>2.8.0</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-mongodb</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-config</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>


<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>

<repositories>
    <repository>
        <id>spring-milestones</id>
        <name>Spring Milestones</name>
        <url>https://repo.spring.io/milestone</url>
    </repository>
</repositories>

I have java 11 everywhere from terminal

ester@ester-HP-Pavilion-Laptop-15-cs3xxx:~$ update-alternatives --list java /usr/lib/jvm/java-11-openjdk-amd64/bin/java

(base) ester@ester-HP-Pavilion-Laptop-15-cs3xxx:~$ $JAVA_HOME bash: /usr/lib/jvm/java-11-openjdk-amd64: Is a directory

also I add system.properties with java.runtime.version=11 Is someone faced this error?

Answer 1

the problem was I had to add in dependencies

   <build>
    <plugins>
        <plugin>
            <groupId>com.heroku.sdk</groupId>
            <artifactId>heroku-maven-plugin</artifactId>
            <version>3.0.3</version>
            <configuration>
                <processTypes>
                    <web>java $JAVA_OPTS -cp target/classes:target/dependency/* YourApplication</web>
                </processTypes>
                <appName>{your app}</appName>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>11</source>
                <target>11</target>
            </configuration>
        </plugin>

    </plugins>
</build>