I’m working on Dockerizing my Maven project and I’m using the following Dockerfile:

# Use an official Maven image as the base image
FROM maven:3.6.0-jdk-11 as builder

# Set the working directory to /app
WORKDIR /app

# Copy the pom.xml file
COPY pom.xml .

# Copy the source code
COPY src/main/java/com/i2i/intern/pixcell/hazelcastoperation /app/src/main/java/com/i2i/intern/pixcell/hazelcastoperation

# Build the project
RUN mvn clean package

# Use an official OpenJDK 11 image as the base image
FROM openjdk:11

# Copy the JAR file from the builder stage
COPY ./target/HazelcastOperation-1.0-SNAPSHOT.jar /app/HazelcastOperation.jar

# Set the default command to run the JAR file
CMD ["java", "-jar", "HazelcastOperation.jar"]

However, I’m encountering an issue when trying to run the container. The container logs always say that the JAR is unable to be accessed or executed.

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.i2i.intern.pixcell</groupId>
    <artifactId>HazelcastOperation</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <java.version>17</java.version>
        <project.build.outputEncoding>UTF-8</project.build.outputEncoding>
        <exec.mainClass>com.i2i.intern.pixcell.hazelcastoperation.HazelcastOperation</exec.mainClass>
    </properties>

    <dependencies>
        <!-- Hazelcast Dependency -->
        <dependency>
            <groupId>com.hazelcast</groupId>
            <artifactId>hazelcast</artifactId>
            <version>5.5.0</version>
        </dependency>
    </dependencies>

   <build>
    <plugins>
        <!-- Maven Compiler Plugin -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>${java.version}</source>
                <target>${java.version}</target>
            </configuration>
        </plugin>

        <!-- Maven Shade Plugin -->
       <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>3.2.4</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <transformers>
                            <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>com.i2i.intern.pixcell.hazelcastoperation.HazelcastOperation</mainClass>
                            </transformer>
                        </transformers>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>
</project>

I’m not sure if I’m missing something in my Maven configuration or Dockerfile setup. Do I need to load Maven and source codes each time, or is there a better way to handle this? Any guidance on resolving the “JAR unable to be accessed” error would be greatly appreciated!