Upgrade Java 8 + Spring Boot 2.0.2 → Java 17 + Spring Boot 3.2.5 with code quality improvements

build.gradle

@@ -1,32 +1,24 @@
-buildscript {
-    repositories {
-        mavenCentral()
-    }
-    dependencies {
-        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.0.2.RELEASE")
-    }
+plugins {
+    id 'java'
+    id 'eclipse'
+    id 'idea'
+    id 'org.springframework.boot' version '3.2.5'
+    id 'io.spring.dependency-management' version '1.1.5'
 }
 
-apply plugin: 'java'
-apply plugin: 'eclipse'
-apply plugin: 'idea'
-apply plugin: 'org.springframework.boot'
-apply plugin: 'io.spring.dependency-management'
-
 bootJar {
-    baseName = 'gs-spring-boot'
-    version =  '0.1.0'
+    archiveBaseName = 'gs-spring-boot'
+    archiveVersion = '0.1.0'
 }
 
 repositories {
     mavenCentral()
 }
 
-sourceCompatibility = 1.8
-targetCompatibility = 1.8
+sourceCompatibility = 17
+targetCompatibility = 17
 
 dependencies {
-    compile("org.springframework.boot:spring-boot-starter-web")
-    testCompile("junit:junit")
+    implementation("org.springframework.boot:spring-boot-starter-web")
+    testImplementation("junit:junit")
 }
-

pom.xml

@@ -5,13 +5,13 @@
 
     <groupId>org.springframework</groupId>
     <artifactId>gs-spring-boot</artifactId>
-    <packaging>pom</packaging>
+    <packaging>jar</packaging>
     <version>0.1.0</version>
 
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.0.2.RELEASE</version>
+        <version>3.2.5</version>
     </parent>
 
     <dependencies>
@@ -35,7 +35,7 @@
     </dependencies>
 
     <properties>
-        <java.version>1.8</java.version>
+        <java.version>17</java.version>
     </properties>
 
 

src/main/java/hello/Application.java

@@ -1,88 +1,12 @@
 package hello;
 
-import java.util.Arrays;
-import java.util.List;
-import java.util.stream.Collectors;
-
-import hello.model.Customer;
-import hello.model.Quote;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.boot.web.client.RestTemplateBuilder;
-import org.springframework.context.ApplicationContext;
-import org.springframework.context.annotation.Bean;
-import org.springframework.jdbc.core.JdbcTemplate;
-import org.springframework.web.client.RestTemplate;
 
 @SpringBootApplication
-public class Application implements CommandLineRunner {
-
-    private static final Logger log = LoggerFactory.getLogger(Application.class);
+public class Application {
 
     public static void main(String[] args) {
-
-        ApplicationContext ctx = SpringApplication.run(Application.class, args);
-
-        System.out.println("Let's inspect the beans provided by Spring Boot:");
-
-        String[] beanNames = ctx.getBeanDefinitionNames();
-        Arrays.sort(beanNames);
-        for (String beanName : beanNames) {
-            System.out.println(beanName);
-        }
-
-        RestTemplate restTemplate =  new RestTemplate();
-        Quote quote = restTemplate.getForObject("http://gturnquist-quoters.cfapps.io/api/random", Quote.class);
-        log.info(quote.toString());
-    }
-
-
-    @Bean
-    public RestTemplate restTemplate(RestTemplateBuilder builder) {
-        return builder.build();
-    }
-
-    @Bean
-    public CommandLineRunner run(RestTemplate restTemplate) throws Exception {
-        return args -> {
-            Quote quote = restTemplate.getForObject(
-                    "http://gturnquist-quoters.cfapps.io/api/random", Quote.class);
-            log.info(quote.toString());
-        };
-    }
-
-
-    @Autowired
-    JdbcTemplate jdbcTemplate;
-
-    @Override
-    public void run(String... args) throws Exception {
-        log.info("Creating tables");
-
-        jdbcTemplate.execute("DROP TABLE customers IF EXISTS");
-        jdbcTemplate.execute("CREATE TABLE customers(id SERIAL, first_name VARCHAR(255), last_name VARCHAR(255))");
-
-        // Split up the array of whole names into an array of first/last names
-        List<Object[]> splitUpNames = Arrays.asList("John Woo", "Jeff Dean", "Josh Bloch", "Josh Long")
-                .stream()
-                .map(name -> name.split(" "))
-                .collect(Collectors.toList());
-
-        // Use a Java 8 stream to print out each tuple of the list
-        splitUpNames.forEach(name -> log.info(String.format("Inserting customer record for %s %s", name[0], name[1])));
-
-        // Uses JdbcTemplate's batchUpdate operation to bulk load data
-        jdbcTemplate.batchUpdate("INSERT INTO customers(first_name, last_name) VALUES (?,?)", splitUpNames);
-
-        log.info("Querying for customer records where first_name = 'Josh':");
-        jdbcTemplate.query(
-                "SELECT id, first_name, last_name FROM customers WHERE first_name = ?", new Object[]{"Josh"},
-                (rs, rowNum) -> new Customer(rs.getLong("id"), rs.getString("first_name"), rs.getString("last_name"))
-        ).forEach(customer -> log.info(customer.toString()));
-
+        SpringApplication.run(Application.class, args);
     }
 }

src/main/java/hello/DataInitializer.java

@@ -0,0 +1,45 @@
+package hello;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import hello.model.Customer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Component;
+
+@Component
+public class DataInitializer implements CommandLineRunner {
+
+    private static final Logger log = LoggerFactory.getLogger(DataInitializer.class);
+
+    @Autowired
+    private JdbcTemplate jdbcTemplate;
+
+    @Override
+    public void run(String... args) throws Exception {
+        log.info("Creating tables");
+
+        jdbcTemplate.execute("DROP TABLE IF EXISTS customers");
+        jdbcTemplate.execute("CREATE TABLE customers(id SERIAL, first_name VARCHAR(255), last_name VARCHAR(255))");
+
+        List<Object[]> splitUpNames = Arrays.asList("John Woo", "Jeff Dean", "Josh Bloch", "Josh Long")
+                .stream()
+                .map(name -> name.split(" "))
+                .collect(Collectors.toList());
+
+        splitUpNames.forEach(name -> log.info(String.format("Inserting customer record for %s %s", name[0], name[1])));
+
+        jdbcTemplate.batchUpdate("INSERT INTO customers(first_name, last_name) VALUES (?,?)", splitUpNames);
+
+        log.info("Querying for customer records where first_name = 'Josh':");
+        jdbcTemplate.query(
+                "SELECT id, first_name, last_name FROM customers WHERE first_name = ?", new Object[]{"Josh"},
+                (rs, rowNum) -> new Customer(rs.getLong("id"), rs.getString("first_name"), rs.getString("last_name"))
+        ).forEach(customer -> log.info(customer.toString()));
+    }
+}

src/main/java/hello/config/AppConfig.java

@@ -0,0 +1,15 @@
+package hello.config;
+
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.RestTemplate;
+
+@Configuration
+public class AppConfig {
+
+    @Bean
+    public RestTemplate restTemplate(RestTemplateBuilder builder) {
+        return builder.build();
+    }
+}

src/main/java/hello/controller/HelloController.java

@@ -2,22 +2,15 @@
 
 import hello.declaration.TimeClient;
 import hello.model.SimpleTimeClient;
-import hello.model.Topic;
 import hello.service.TopicService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.bind.annotation.RequestMapping;
 
 import java.time.LocalDate;
 import java.time.LocalDateTime;
-import java.time.LocalTime;
 import java.time.ZoneId;
-import java.time.chrono.ChronoPeriod;
 import java.time.temporal.ChronoUnit;
-import java.util.List;
-import java.util.regex.Pattern;
-import java.util.stream.Collector;
-import java.util.stream.Collectors;
 
 @RestController
 public class HelloController {

src/main/java/hello/model/Topic.java

@@ -1,5 +1,6 @@
 package hello.model;
 
+import java.util.Objects;
 
 public class Topic {
     private String id;
@@ -40,4 +41,27 @@ public Topic(String id, String subjectName, String subjectDescription) {
         this.subjectDescription = subjectDescription;
     }
 
+    @Override
+    public String toString() {
+        return "Topic{" +
+                "id='" + id + '\'' +
+                ", subjectName='" + subjectName + '\'' +
+                ", subjectDescription='" + subjectDescription + '\'' +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Topic topic = (Topic) o;
+        return Objects.equals(id, topic.id) &&
+                Objects.equals(subjectName, topic.subjectName) &&
+                Objects.equals(subjectDescription, topic.subjectDescription);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, subjectName, subjectDescription);
+    }
 }

src/main/java/hello/service/TopicService.java

@@ -10,6 +10,7 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.*;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
@@ -19,7 +20,7 @@
 public class TopicService {
 
 
-    private List<Topic> topics = new ArrayList<>(Arrays.asList(
+    private List<Topic> topics = new CopyOnWriteArrayList<>(Arrays.asList(
             new Topic("spring", "Spring Framework", "Spring Framework Description"),
             new Topic("java", "Core Java", "Java Description"),
             new Topic("javascript", "javascript Framework", "javascript Framework Description")
@@ -36,7 +37,8 @@ public List<Topic> getAllTopics() {
      * @return
      */
     public Topic getTopicWithId(String id) {
-        return topics.stream().filter(topic -> topic.getId().equals(id)).findFirst().get();
+        return topics.stream().filter(topic -> topic.getId().equals(id)).findFirst()
+                .orElseThrow(() -> new NoSuchElementException("Topic not found with id: " + id));
     }
 
     public void addTopic(Topic topic) {
@@ -96,8 +98,9 @@ private static List<Topic> printTopicsWithPredicate(List<Topic> topicList, Custo
      * @return
      */
     public List<Topic> sortTopicsWithID() {
-        topics.sort(Comparator.comparing(Topic::getId));
-        return topics;
+        List<Topic> sorted = new ArrayList<>(topics);
+        sorted.sort(Comparator.comparing(Topic::getId));
+        return sorted;
     }