BAEL-3091: The Prototype Pattern in Java (changed code based on valid comments from a reader)

spring-boot-deployment/README.md

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+## Spring Boot Deployment
+
+This module contains articles about deployment of a Spring Boot Application
+
+### Relevant Articles:			
+ - [Deploy a Spring Boot WAR into a Tomcat Server](https://www.baeldung.com/spring-boot-war-tomcat-deploy)
+ - [Spring Boot Console Application](https://www.baeldung.com/spring-boot-console-app)
+ - [How to Configure Spring Boot Tomcat](https://www.baeldung.com/spring-boot-configure-tomcat)
+ - [Comparing Embedded Servlet Containers in Spring Boot](https://www.baeldung.com/spring-boot-servlet-containers)

spring-boot-deployment/pom.xml

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+<?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>
+    <artifactId>spring-boot-deployment</artifactId>
+    <name>spring-boot-deployment</name>
+    <packaging>war</packaging>
+    <description>Demo project for Spring Boot</description>
+
+    <parent>
+        <artifactId>parent-boot-2</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-boot-2</relativePath>
+    </parent>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-thymeleaf</artifactId>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-mail</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-actuator</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>javax.persistence</groupId>
+            <artifactId>javax.persistence-api</artifactId>
+            <version>${jpa.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.subethamail</groupId>
+            <artifactId>subethasmtp</artifactId>
+            <version>${subethasmtp.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.webjars</groupId>
+            <artifactId>bootstrap</artifactId>
+            <version>${bootstrap.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.webjars</groupId>
+            <artifactId>jquery</artifactId>
+            <version>${jquery.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-context</artifactId>
+            <version>${springcloud.version}</version>
+        </dependency>
+        
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>${httpclient.version}</version>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <finalName>${project.artifactId}</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+                <excludes>
+                    <exclude>**/conf.properties</exclude>
+                </excludes>
+            </resource>
+        </resources>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                        <configuration>
+                            <mainClass>com.baeldung.webjar.WebjarsdemoApplication</mainClass>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-failsafe-plugin</artifactId>
+                <version>2.18</version>
+                <executions>
+                    <!-- Invokes both the integration-test and the verify goals of the Failsafe 
+                        Maven plugin -->
+                    <execution>
+                        <id>integration-tests</id>
+                        <goals>
+                            <goal>integration-test</goal>
+                            <goal>verify</goal>
+                        </goals>
+                        <configuration>
+                            <!-- Skips integration tests if the value of skip.integration.tests 
+                                property is true -->
+                                <includes>
+                                        <include>**/ExternalPropertyFileLoaderIntegrationTest.java</include>
+                                    </includes>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <profiles>
+        <profile>
+            <id>autoconfiguration</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-surefire-plugin</artifactId>
+                        <executions>
+                            <execution>
+                                <phase>integration-test</phase>
+                                <goals>
+                                    <goal>test</goal>
+                                </goals>
+                                <configuration>
+                                    <excludes>
+                                        <exclude>**/*LiveTest.java</exclude>
+                                        <exclude>**/*IntegrationTest.java</exclude>
+                                        <exclude>**/*IntTest.java</exclude>
+                                    </excludes>
+                                    <includes>
+                                        <include>**/AutoconfigurationTest.java</include>
+                                    </includes>
+                                </configuration>
+                            </execution>
+                        </executions>
+                        <configuration>
+                            <systemPropertyVariables>
+                                <test.mime>json</test.mime>
+                            </systemPropertyVariables>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
+    
+    <properties>
+        <!-- The main class to start by executing java -jar -->
+        <start-class>org.baeldung.boot.Application</start-class>
+        <jquery.version>3.1.1</jquery.version>
+        <bootstrap.version>3.3.7-1</bootstrap.version>
+        <jpa.version>2.2</jpa.version>
+        <guava.version>18.0</guava.version>
+        <subethasmtp.version>3.1.7</subethasmtp.version>
+        <springcloud.version>2.0.2.RELEASE</springcloud.version>
+        <httpclient.version>4.5.8</httpclient.version>
+    </properties>
+
+</project>

spring-boot-deployment/src/main/java/com/baeldung/compare/ComparisonApplication.java

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+package com.baeldung.compare;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ComparisonApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(ComparisonApplication.class, args);
+	}
+}

spring-boot-deployment/src/main/java/com/baeldung/compare/StartupEventHandler.java

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+package com.baeldung.compare;
+
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.BiFunction;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.context.event.ApplicationReadyEvent;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+import io.micrometer.core.instrument.Meter;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Statistic;
+
+@Component
+public class StartupEventHandler {
+
+    // logger, constructor
+    private static Logger logger = LoggerFactory.getLogger(StartupEventHandler.class);
+    
+    public StartupEventHandler(MeterRegistry registry) {
+        this.meterRegistry = registry;
+    }
+    
+    private String[] METRICS = {
+      "jvm.memory.used", 
+      "jvm.classes.loaded", 
+      "jvm.threads.live"};
+
+    private String METRIC_MSG_FORMAT = "Startup Metric >> {}={}";
+    
+    private MeterRegistry meterRegistry;
+
+    @EventListener
+    public void getAndLogStartupMetrics(
+      ApplicationReadyEvent event) {
+        Arrays.asList(METRICS)
+          .forEach(this::getAndLogActuatorMetric);
+    }
+
+    private void getAndLogActuatorMetric(String metric) {
+        Meter meter = meterRegistry.find(metric).meter();
+        Map<Statistic, Double> stats = getSamples(meter);
+ 
+        logger.info(METRIC_MSG_FORMAT, metric, stats.get(Statistic.VALUE).longValue());
+    }
+
+    private Map<Statistic, Double> getSamples(Meter meter) {
+        Map<Statistic, Double> samples = new LinkedHashMap<>();
+        mergeMeasurements(samples, meter);
+        return samples;
+    }
+
+    private void mergeMeasurements(Map<Statistic, Double> samples, Meter meter) {
+        meter.measure().forEach((measurement) -> samples.merge(measurement.getStatistic(),
+                measurement.getValue(), mergeFunction(measurement.getStatistic())));
+    }
+
+    private BiFunction<Double, Double, Double> mergeFunction(Statistic statistic) {
+        return Statistic.MAX.equals(statistic) ? Double::max : Double::sum;
+    }    
+}

spring-boot-deployment/src/main/java/com/baeldung/gracefulshutdown/GracefulShutdownApplication.java

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+package com.baeldung.gracefulshutdown;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class GracefulShutdownApplication {
+
+    public static void main(String args[]) {
+        SpringApplication.run(GracefulShutdownApplication.class, args);
+    }
+}

spring-boot-deployment/src/main/java/com/baeldung/gracefulshutdown/beans/LongRunningProcessBean.java

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+package com.baeldung.gracefulshutdown.beans;
+
+import javax.annotation.PostConstruct;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.task.TaskExecutor;
+import org.springframework.stereotype.Component;
+
+@Component
+public class LongRunningProcessBean {
+
+    private static final Logger LOG = LoggerFactory.getLogger(LongRunningProcessBean.class);
+
+    @Autowired
+    private TaskExecutor taskExecutor;
+
+    @PostConstruct
+    public void runTaskOnStartup() {
+        LOG.info("runTaskOnStartup entering");
+        for (int i = 0; i < 3; i++) {
+            final int processNumber = i;
+            taskExecutor.execute(() -> {
+                try {
+                    LOG.info("Long running process {} using threadpool started", processNumber);
+                    Thread.sleep(60_000);
+                    LOG.info("Long running process {} using threadpool completed", processNumber);
+                } catch (Exception e) {
+                    LOG.error("Error while executing task", e);
+                }
+            });
+        }
+        LOG.info("runTaskOnStartup exiting");
+    }
+}

spring-boot-deployment/src/main/java/com/baeldung/gracefulshutdown/config/SpringConfiguration.java

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+package com.baeldung.gracefulshutdown.config;
+
+import javax.annotation.PreDestroy;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.task.TaskExecutor;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+
+@Configuration
+public class SpringConfiguration {
+
+    private static final Logger LOG = LoggerFactory.getLogger(SpringConfiguration.class);
+
+    @Bean
+    public TaskExecutor taskExecutor() {
+        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
+        taskExecutor.setCorePoolSize(2);
+        taskExecutor.setMaxPoolSize(2);
+        taskExecutor.setWaitForTasksToCompleteOnShutdown(true);
+        taskExecutor.setAwaitTerminationSeconds(30);
+        taskExecutor.initialize();
+        return taskExecutor;
+    }
+
+    @PreDestroy
+    public void destroy() {
+        LOG.info("Shutdown initiated");
+    }
+}

spring-boot-deployment/src/main/java/com/baeldung/springbootconfiguration/SpringBootConfigurationApplication.java

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+package com.baeldung.springbootconfiguration;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SpringBootConfigurationApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringBootConfigurationApplication.class, args);
+    }
+
+}

spring-boot-deployment/src/main/java/com/baeldung/springbootconfiguration/controller/GreetingsController.java

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+package com.baeldung.springbootconfiguration.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class GreetingsController {
+
+    @GetMapping("/greetings/{username}")
+    public String getGreetings(@PathVariable("username") String userName) {
+        return "Hello " + userName + ", Good day...!!!";
+    }
+}

spring-boot-deployment/src/main/java/com/baeldung/springbootnonwebapp/SpringBootConsoleApplication.java

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+package com.baeldung.springbootnonwebapp;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * 1. Act as main class for spring boot application
+ * 2. Also implements CommandLineRunner, so that code within run method
+ * is executed before application startup but after all beans are effectively created
+ * @author hemant
+ *
+ */
+@SpringBootApplication
+public class SpringBootConsoleApplication implements CommandLineRunner {
+
+	private static Logger LOG = LoggerFactory.getLogger(SpringBootConsoleApplication.class);
+
+	public static void main(String[] args) {
+		LOG.info("STARTING THE APPLICATION");
+		SpringApplication.run(SpringBootConsoleApplication.class, args);
+		LOG.info("APPLICATION FINISHED");
+	}
+
+	/**
+	 * This method will be executed after the application context is loaded and
+	 * right before the Spring Application main method is completed.
+	 */
+	@Override
+	public void run(String... args) throws Exception {
+		LOG.info("EXECUTING : command line runner");
+    		for (int i = 0; i < args.length; ++i) {
+        		LOG.info("args[{}]: {}", i, args[i]);
+    		}
+	}
+}

spring-boot-deployment/src/main/java/com/baeldung/springbootsimple/SpringBootTomcatApplication.java

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+package com.baeldung.springbootsimple;
+
+import org.springframework.boot.*;
+import org.springframework.boot.autoconfigure.*;
+import org.springframework.boot.web.servlet.support.*;
+
+@SpringBootApplication
+public class SpringBootTomcatApplication extends SpringBootServletInitializer {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringBootTomcatApplication.class, args);
+    }
+}

spring-boot-deployment/src/main/java/com/baeldung/springbootsimple/TomcatController.java

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+package com.baeldung.springbootsimple;
+
+import org.springframework.web.bind.annotation.*;
+
+import java.util.*;
+import java.util.stream.*;
+
+@RestController
+public class TomcatController {
+
+    @GetMapping(value = "/hello")
+    public Collection<String> sayHello() {
+        return IntStream.range(0, 10)
+                .mapToObj(i -> "Hello number " + i)
+                .collect(Collectors.toList());
+    }
+
+}

spring-boot-deployment/src/main/resources/application.properties

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+management.endpoints.web.exposure.include=*
+management.metrics.enable.root=true
+management.metrics.enable.jvm=true
+management.endpoint.restart.enabled=true
+spring.datasource.jmx-enabled=false
+spring.main.allow-bean-definition-overriding=true
+management.endpoint.shutdown.enabled=true

spring-boot-deployment/src/main/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

spring-boot-deployment/src/test/java/com/baeldung/springbootconfiguration/SpringContextIntegrationTest.java

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+package com.baeldung.springbootconfiguration;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class SpringContextIntegrationTest {
+
+    @Test
+    public void contextLoads() {
+    }
+}

spring-boot-deployment/src/test/java/com/baeldung/springbootconfiguration/SpringContextTest.java

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+package com.baeldung.springbootconfiguration;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class SpringContextTest {
+
+    @Test
+    public void contextLoads() {
+    }
+}

spring-boot-deployment/src/test/java/com/baeldung/springbootsimple/SpringBootTomcatApplicationIntegrationTest.java

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+package com.baeldung.springbootsimple;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class SpringBootTomcatApplicationIntegrationTest {
+
+	@Test
+	public void contextLoads() {
+	}
+
+}