与Firebase数据库集成的Spring代码在IDE上可以正常工作，但在Tomcat上却不能

Question

I have a spring boot web application (non-android). There is a method named initializeComments and this is annotated with @PostConstruct. This method reads data from firebase database. This same exact application code works on Eclipse IDE but NOT when i copy this war file to a tomcat container and run it using tomcat/bin/startup.sh script. I have spent lot of time trying to debug and research but am not able to find any solutions. So posting to this forum for help. Appreciate if anyone can provide any pointers.

@PostConstruct
    void initializeComments()
    {
        log.info("initializeComments::");
        final CountDownLatch done = new CountDownLatch(1);
        log.info("initializeComments::firebaseDatabseComments::"+firebaseDatabseComments.toString());
        // Load all comments
        firebaseDatabseComments.addListenerForSingleValueEvent(new ValueEventListener() 
        {
            public void onDataChange(DataSnapshot snapshot) 
            {
                for (DataSnapshot child : snapshot.getChildren()) 
                {
                    String key= child.getKey();
                    List<String> onlycomments = new ArrayList<String>();
                    for (DataSnapshot subchild : child.getChildren()) 
                    {
                          String value = (String) subchild.getValue();
                          onlycomments.add(value);
                    }
                    comments.put(key, onlycomments);
                 }
                log.info("initializePosts::comments: " + comments.toString());
                 done.countDown();
            }

            public void onCancelled(DatabaseError databaseError) 
            {
                log.info("initializeComments::The read failed for comments: " + databaseError.getCode());
            }
        });

        try 
        {
            done.await();
        } 
        catch (InterruptedException e) 
        {
            e.printStackTrace();
        }
    }

my pom file:

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> 
  </parent>

  <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.M9</spring-cloud.version>
  </properties>

    <dependencies>
        <dependency>
            <groupId>com.google.firebase</groupId>
            <artifactId>firebase-admin</artifactId>
            <version>6.7.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.4.0</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.4.0</version>
        </dependency>
        <dependency>
            <groupId>io.dropwizard.metrics</groupId>
            <artifactId>metrics-core</artifactId>
        </dependency>
        <dependency>
            <groupId>io.dropwizard.metrics</groupId>
            <artifactId>metrics-json</artifactId>
        </dependency>
        <dependency>
            <groupId>io.dropwizard.metrics</groupId>
            <artifactId>metrics-annotation</artifactId>
        </dependency>
        <dependency>
            <groupId>com.ryantenney.metrics</groupId>
            <artifactId>metrics-spring</artifactId>
            <version>3.1.3</version>
        </dependency>
        <dependency>
            <groupId>de.codecentric</groupId>
            <artifactId>spring-boot-admin-starter-client</artifactId>
            <version>1.5.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.glassfish</groupId>
            <artifactId>javax.json</artifactId>
            <version>1.0.4</version>
        </dependency>
         <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
         </dependency>
         <dependency>
             <groupId>javax.servlet</groupId>
             <artifactId>jstl</artifactId>
       </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Camden.SR7</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <executable>true</executable>
                </configuration>
            </plugin>           
        </plugins>
    </build>

When i run on Eclipse IDE i am able to read all the posts successfully using the same exact code. But when i run on tomcat (the war file), it just hangs and never exits. I don't receive any async response. I have handled the CountDownLatch piece also to ensure it does not exit before the main function returns. So where am i going wrong here?

Answer 1

finally found the issue by enabling debug logs in firebase... seems the clock was not synchronized. After doing an ntp sync the issue was resolved.