java SpringBoot jar crashes on CentOS

Question

I have a very simple SpringBoot application which implements a simple Rest API.

This is the way I start it:

package API;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Main {

    public static void main(String args[]){
        SpringApplication.run(Main.class);
    }
}

The controller is placed in the same package as this one (the API package).

This is my maven file:

<?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>HadoopDriver</groupId>
    <artifactId>HadoopDriver</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.2.RELEASE</version>
    </parent>

    <properties>
        <tomcat.version>8.0.30</tomcat.version>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.0.2.RELEASE</version>
                <configuration>
                    <executable>true</executable>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-framework-bom</artifactId>
            <version>5.0.6.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>

        <dependency>
            <groupId>com.amazonaws</groupId>
            <artifactId>aws-java-sdk-sns</artifactId>
            <version>1.11.338</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-yarn-client</artifactId>
            <version>3.1.0</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.0.6.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.0.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <version>2.0.2.RELEASE</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.jayway.jsonpath</groupId>
            <artifactId>json-path</artifactId>
            <version>2.0.0</version>
        </dependency>
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.2</version>
        </dependency>


        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
            <version>2.6.1</version>
            <scope>compile</scope>
            <exclusions>
                <exclusion>
                    <groupId>javax.servlet</groupId>
                    <artifactId>servlet-api</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-hdfs</artifactId>
            <version>2.6.1</version>
            <scope>compile</scope>
            <exclusions>
                <exclusion>
                    <groupId>javax.servlet</groupId>
                    <artifactId>servlet-api</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <repositories>
        <repository>
            <id>spring-releases</id>
            <url>https://repo.spring.io/libs-release</url>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>repository.spring.release</id>
            <name>Spring GA Repository</name>
            <url>https://repo.spring.io/plugins-release/</url>
        </pluginRepository>
    </pluginRepositories>
</project>

I develop this app in IntelliJ Idea, on macOS and I generate a JAR that I place on a Cent OS (EC2) machine and I want to run it from there.

I generate the manifest file like that: File -> Project Structure -> Artifacts -> + -> JAR -> From Modules with dependencies -> select the Main class -> change the directory of the META-INF to /resources instead of /java -> Apply -> OK .

The I go on Build -> Build Artifacts -> Build and then I get my JAR that is placed in the /out/artifacts/project_jar folder.

I upload this jar to the Cent OS machine and when I try to run it I get the following output:

user@host>
log4j:WARN No appenders could be found for logger (org.springframework.web.context.support.StandardServletEnvironment).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::
user@host>

I get no error message, no nothing. I don't know where to look for errors, I don't have any clue on how to solve this issue.

Please tell me at least where to look, how can I diagnose this problem because I'm trying for a lot of time with no result.

Answer 1

You don't want to use Log4J in your application, for a couple of reasons:

• It's at end of life
• Spring Boot already ships with Logback and other ways to configure logging

In your case, you may not be getting enough detail in your logs. Crank up the verbosity by adding this to your application.properties file:

logging.level.org.springframework=debug

This will allow you to see debug logs in stdout from everything living underneath org.springframework .