Migrate from Java 8 to Java 15 with Spring Boot 2.7.18

.mvn/wrapper/maven-wrapper.properties

@@ -1 +1 @@
-distributionUrl=https://repo1.maven.org/maven2/org/apache/maven/apache-maven/3.3.9/apache-maven-3.3.9-bin.zip
+distributionUrl=https://repo1.maven.org/maven2/org/apache/maven/apache-maven/3.9.6/apache-maven-3.9.6-bin.zip

README.md

@@ -1,5 +1,5 @@
-# springboot-java8
-The project is made on spring boot. The project summarize the new features present in Java 8.
+# springboot-java15
+The project is made on spring boot. The project summarizes the features present in Java 8 through Java 15.
 It contain list of harcoded topics list. You can call the apis's with POSTMAN to add,delete,update Topic list
 In addition, it uses 
 1) Java 8 NIO methods 
@@ -13,6 +13,8 @@ In addition, it uses
 9) Default and Static methods in interface
 10) Java 8 LocalDateTime API
 11) Pattern
+12) Java 10+ local variable type inference (var)
+13) Java 15 text blocks
 
 
 
@@ -76,13 +78,12 @@ GET /datetime
 
 ### Prerequisites
 
-1) Java sdk
+1) Java 15 SDK
 2) POSTMAN
 
 ### Installing
 
 
-
 ```
 1) Download or clone
 2) Import the project
@@ -129,6 +130,4 @@ https://dzone.com/articles/java-8-friday-goodies-new-new
 
 ## Authors
 
-* **Rehman Murad Ali** 
-
-
+* **Rehman Murad Ali**

build.gradle

@@ -3,7 +3,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.0.2.RELEASE")
+        classpath("org.springframework.boot:spring-boot-gradle-plugin:2.7.18")
     }
 }
 
@@ -14,19 +14,20 @@ 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 = 15
+targetCompatibility = 15
 
 dependencies {
-    compile("org.springframework.boot:spring-boot-starter-web")
-    testCompile("junit:junit")
+    implementation("org.springframework.boot:spring-boot-starter-web")
+    implementation("org.springframework.boot:spring-boot-starter-jdbc")
+    runtimeOnly("com.h2database:h2")
+    testImplementation("junit:junit")
 }
-

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6.4-bin.zip

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>2.7.18</version>
     </parent>
 
     <dependencies>
@@ -35,12 +35,20 @@
     </dependencies>
 
     <properties>
-        <java.version>1.8</java.version>
+        <java.version>15</java.version>
     </properties>
 
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <release>15</release>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-maven-plugin</artifactId>

src/main/java/hello/Application.java

@@ -25,19 +25,25 @@ public class Application implements CommandLineRunner {
 
     public static void main(String[] args) {
 
-        ApplicationContext ctx = SpringApplication.run(Application.class, args);
-        
+        var ctx = SpringApplication.run(Application.class, args);
+
         System.out.println("Let's inspect the beans provided by Spring Boot:");
-        
-        String[] beanNames = ctx.getBeanDefinitionNames();
+
+        var beanNames = ctx.getBeanDefinitionNames();
         Arrays.sort(beanNames);
-        for (String beanName : beanNames) {
+        for (var 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());
+        try {
+            var restTemplate = new RestTemplate();
+            var quote = restTemplate.getForObject("https://dummyjson.com/quotes/random", Quote.class);
+            if (quote != null) {
+                log.info(quote.toString());
+            }
+        } catch (Exception e) {
+            log.warn("Could not fetch quote from external service: {}", e.getMessage());
+        }
     }
 
 
@@ -49,9 +55,15 @@ public RestTemplate restTemplate(RestTemplateBuilder builder) {
     @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());
+            try {
+                var quote = restTemplate.getForObject(
+                        "https://dummyjson.com/quotes/random", Quote.class);
+                if (quote != null) {
+                    log.info(quote.toString());
+                }
+            } catch (Exception e) {
+                log.warn("Could not fetch quote from external service: {}", e.getMessage());
+            }
         };
     }
 
@@ -64,23 +76,26 @@ 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")
+        jdbcTemplate.execute("""
+                CREATE TABLE customers(
+                    id SERIAL,
+                    first_name VARCHAR(255),
+                    last_name VARCHAR(255)
+                )""");
+
+        List<Object[]> splitUpNames = List.of("John Woo", "Jeff Dean", "Josh Bloch", "Josh Long")
                 .stream()
-                .map(name -> name.split(" "))
+                .map(name -> (Object[]) 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"},
+                "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/controller/HelloController.java

@@ -2,100 +2,89 @@
 
 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 {
 
-
-    String joinTemplate = "Joining All String ID's with JOIN method: ";
-    String makeDistinctAndSortCharactersTemplate = "-------------Get all ID characters, select distict and sort with ID=   ";
-    String splitAllIdWithColonSelectIDWithJavaKeywordThenSortThenJoinTemplate = "-------------Split All Id With Colon," +
-            "Select ID With \"Java\" Keyword," +
-            " Then Sort Then Join ";
-    String findIdHavingCharacterTemplate = "-------------Return All ID having character \'g\' in it:  ";
-    String findAllFilesInPathAndSortTemplate = "---------Find all files in path and sort:    ";
-    String findParticularFileInPathAndSortTemplate = "----------Find File in present directory which strats with \"grad\",provided maximum depth=25 and sort : ";
-    String findParticularFileInPathAndSortWithWalkFunctionTemplate = "----------Find File in present directory which strats with \"grad\",provided maximum depth=25 and sort :  with walk function";
-    String readFileWithStreamFunctionTemplate = "---------Read \"temp.txt\" file with stream functions, having \"print\" witin it:  ";
-
-
     @Autowired
     private TopicService topicService;
 
     /**
      * Java 8 Date Time example
-     *
-     * @return
      */
     @RequestMapping("/datetime")
     public String index() {
-        TimeClient myTimeClient = new SimpleTimeClient();
-        LocalDateTime localDateTime = LocalDateTime.now();
-        return "Greetings from Spring Boot! ----------------------" +
-                "Datetime now is " + String.valueOf(myTimeClient.toString()) + "----------------------" +
-                "Datetime tomorrow will be " + String.valueOf(myTimeClient.getLocalDateTime().plusDays(1)) + "----------------------" +
-                "Datetime of previous month was " + String.valueOf(myTimeClient.getLocalDateTime().minus(1, ChronoUnit.MONTHS)) + "----------------------" +
-                "Is this a leap year ?  " + String.valueOf(LocalDate.now().isLeapYear()) + "----------------------" +
-                "Default system zone id   " + String.valueOf(ZoneId.systemDefault()) + "-------------------" +
-                "Time in California: " + myTimeClient.getZonedDateTime("Canada/Central").toString();
-
+        var myTimeClient = new SimpleTimeClient();
+        return """
+                Greetings from Spring Boot! ----------------------\
+                Datetime now is %s----------------------\
+                Datetime tomorrow will be %s----------------------\
+                Datetime of previous month was %s----------------------\
+                Is this a leap year ?  %s----------------------\
+                Default system zone id   %s-------------------\
+                Time in California: %s""".formatted(
+                myTimeClient,
+                myTimeClient.getLocalDateTime().plusDays(1),
+                myTimeClient.getLocalDateTime().minus(1, ChronoUnit.MONTHS),
+                LocalDate.now().isLeapYear(),
+                ZoneId.systemDefault(),
+                myTimeClient.getZonedDateTime("Canada/Central"));
     }
 
 
     /**
      * String Operations in Java 8
-     *
-     * @return
      */
     @RequestMapping("/topic/string/operation")
     public String showStringOperation() {
-
-        String join = topicService.returnAllTopicIDWithStringSlicing();
-        String makeDistinctAndSortCharacters = topicService.makeDistinctAndSortCharacters(join);
-        String splitAllIdWithColonSelectIDWithJavaKeywordThenSortThenJoin = topicService
+        var join = topicService.returnAllTopicIDWithStringSlicing();
+        var makeDistinctAndSortCharacters = topicService.makeDistinctAndSortCharacters(join);
+        var splitResult = topicService
                 .splitAllIdWithColonSelectIDWithJavaKeywordThenSortThenJoin(join);
-        String findIdHavingCharacter = topicService.findIdHavingCharacter();
-
-        return joinTemplate + join
-                + makeDistinctAndSortCharactersTemplate + makeDistinctAndSortCharacters
-                + splitAllIdWithColonSelectIDWithJavaKeywordThenSortThenJoinTemplate + splitAllIdWithColonSelectIDWithJavaKeywordThenSortThenJoin
-                + findIdHavingCharacterTemplate + findIdHavingCharacter;
-
+        var findIdHavingCharacter = topicService.findIdHavingCharacter();
+
+        return """
+                Joining All String ID's with JOIN method: %s\
+                -------------Get all ID characters, select distict and sort with ID=   %s\
+                -------------Split All Id With Colon,\
+                Select ID With "Java" Keyword,\
+                 Then Sort Then Join %s\
+                -------------Return All ID having character 'g' in it:  %s""".formatted(
+                join,
+                makeDistinctAndSortCharacters,
+                splitResult,
+                findIdHavingCharacter);
     }
 
 
     /**
      * File Operation in Java 8
-     * @return
      */
     @RequestMapping("/topic/file/operation")
     public String showFileOperation() {
-        String findAllFilesInPathAndSort = topicService.findAllFilesInPathAndSort();
-        String findParticularFileInPathAndSort = topicService.findParticularFileInPathAndSort();
-        String findParticularFileInPathAndSortWithWalkFunction = topicService.findParticularFileInPathAndSortWithWalkFunction();
-        String readFileWithStreamFunction = topicService.readFileWithStreamFunction();
-        return findAllFilesInPathAndSortTemplate + findAllFilesInPathAndSort
-                + findParticularFileInPathAndSortTemplate + findParticularFileInPathAndSort
-                + findParticularFileInPathAndSortWithWalkFunctionTemplate + findParticularFileInPathAndSortWithWalkFunction
-                + readFileWithStreamFunctionTemplate + readFileWithStreamFunction;
+        var findAllFilesInPathAndSort = topicService.findAllFilesInPathAndSort();
+        var findParticularFileInPathAndSort = topicService.findParticularFileInPathAndSort();
+        var findWithWalk = topicService.findParticularFileInPathAndSortWithWalkFunction();
+        var readFile = topicService.readFileWithStreamFunction();
+        return """
+                ---------Find all files in path and sort:    %s\
+                ----------Find File in present directory which strats with "grad",\
+                provided maximum depth=25 and sort : %s\
+                ----------Find File in present directory which strats with "grad",\
+                provided maximum depth=25 and sort :  with walk function%s\
+                ---------Read "temp.txt" file with stream functions, having "print" witin it:  %s""".formatted(
+                findAllFilesInPathAndSort,
+                findParticularFileInPathAndSort,
+                findWithWalk,
+                readFile);
     }
 
-
-
 }