Set the record straight

• We learned Java because it was the 'hipster' lang
• C and COBOL were the old domain
• Garbage Collection and Object Oriented FTW!

Web Apps?

• We wrote Web apps before JSPs on Netscape
• Instead of Apache mod_cgi and perl

Javascript?

• We wrote Javascript (DHTML) before it was cool!
• CSS when it wasn't LESS or SASS
• AJAX before the blog post calling it AJAX

Where did it all go wrong?

Java's Image Problem

• NodeJS, Ruby, Go, Swift, etc
• Code Verbosity and Ceremony
• Too "enterprisey"
• App Servers

JVM Languages Help

• Groovy and Scala and JRuby, etc...
• Groovy was Swift before Swift
• Kotlin (aka Scala the good parts)

Java's Speed Problem

• Not app performance
• Java wins that battle (see Netflix)
• "Velocity on the JVM is the Killer App" - Andy Glover
• But speed-to-market
• Hard to jumpstart
• XML everywhere
• App Servers

Spicing up Java's Image

• Spring Boot
  • Write an app in a tweet! (so hipster)
  • Opinionated Spring all wired up
  • Production-ready by default
  • No App Server Required - executable Jars
• JHipster
  • Full stack AngularJS + Spring Boot
  • JS Build Tools
  • Beautiful Metrics
  • JHipster-loaded
• Groovy Ecosystem
  • Groovy / Spock / Gradle / gvm / Grails
• Others - Dropwizard, Akka, Vert.x

Spring Boot!  

• Opinionated Spring all wired up
• 100% Java Config (no XML!)
• Executable Jars, embedded web server (or not)
• Sane Profiles and Properties
• Easy REST & Microservices
• Spring Data JPA - dynamic finders (grails style)
• Production-ready by default

Boot Install and CLI

• gvm install springboot
• A full tweet-sized 140 character app:
• spring run GBR.groovy

@RestController
  class GBR {
      @RequestMapping("/")
      String gbr() {
          "Go Big Red! #Nebrasketball"
      }
  }

Jumpstart a Real Boot App

• start.spring.io INITIALIZR
• a la carte selection menu

Embedded Web Container

• Just run as a main class in a jar
• Great for cloud deploys. Microservices. Fat Jars.
• Weblogic, Websphere, JBoss, etc NOT REQUIRED
• gradle bootRun
• java -jar appname.jar
• Or run Main class from IDE

Or generate a War

• gradle war
• mvn package (also an executable jar file)
• Warning Disclaimer:
• Running latest of any Java stack on Websphere/Weblogic is tricky. Especially Hibernate/JPA.
• Because classloaders...
• It can be done
• Get your Google / Stackoverflow keyword search game right

Java Config

• No XML, all Java Config (unless you like XML)

@Configuration
  @EnableAutoConfiguration
  @ComponentScan
  public class Application {
  
      public static void main(String[] args) {
          SpringApplication.run(Application.class, args);
      }
      
  }

Everything is all wired up

• No fiddling with hooking it all together
• Production-ready out of the box

Profiles

• Important piece of Spring Boot
• dev/test/prod profiles
• Available in core Spring too, but Boot leans on them

Properties

• Hierarchical properties
• application-*.properties, application.properties, System Props, JNDI Var, JVM Arg, ...

Boot-style Props in raw Spring

public class PropertiesInitializer implements ApplicationContextInitializer {
public void initialize(ConfigurableApplicationContext applicationContext) {
    ConfigurableEnvironment env = applicationContext.getEnvironment();
    
    String[] activeProfiles = getActiveProfiles(env);
    
    for (String profileName : activeProfiles) {
        log.info("Loading properties for Spring Active Profile: {}", profileName);
        try {
            ResourcePropertySource propertySource = new ResourcePropertySource(profileName
             + "EnvProperties", "classpath:application-" + profileName + ".properties");
             
            env.getPropertySources().addLast(propertySource);
        } catch (IOException e) {
            log.error("ERROR during environment properties setup - TRYING TO LOAD: " + profileName, e);
            
            //Okay to silently fail here, as we might have profiles
            // that do not have properties files (like dev1, dev2, etc)
        }
    }
}

Database Props

public class SpringPropertiesConfig {
@PostConstruct
public void initializeDatabasePropertySourceUsage() {
    MutablePropertySources propertySources = ((ConfigurableEnvironment) env).getPropertySources();
    
    try {
        //dataSource, Table Name, Key Column, Value Column
        DatabaseConfiguration databaseConfiguration = new DatabaseConfiguration(dataSource(), "AppConfiguration", "propertyKey", "propertyValue");
        
        //CommonsConfigurationFactoryBean comes from https://java.net/projects/springmodules/sources/svn/content/tags/release-0_8/projects/commons/src/java/org/springmodules/commons/configuration/CommonsConfigurationFactoryBean.java?rev=2110
        //Per https://jira.spring.io/browse/SPR-10213 I chose to just copy the raw source into our project
        CommonsConfigurationFactoryBean commonsConfigurationFactoryBean = new CommonsConfigurationFactoryBean(databaseConfiguration);
        
        Properties dbProps = (Properties) commonsConfigurationFactoryBean.getObject();
        PropertiesPropertySource dbPropertySource = new PropertiesPropertySource("dbPropertySource", dbProps);
        
        //By being First, Database Properties take precedence over all other properties that have the same key name
        //You could put this last, or just in front of the application.properties if you wanted to...
        propertySources.addFirst(dbPropertySource);
    } catch (Exception e) {
        log.error("Error during database properties setup", e);
        throw new RuntimeException(e);
    }
}

Spring Data JPA

• Simple CRUD Repositories
• (findAll, create, update, delete, and more)
• Dynamic Finders

public interface AttendeeRepository extends JpaRepository {

    List findByOrderByNameDesc();
    
    List findByNameOrderByNameAsc(String name);
    
    List findByOrderByNameAsc();
}

Spring Data REST

• Easy REST Entities
• HATEOAS enabled
• Better for quick prototypes than prod (customization)

@RepositoryRestResource(collectionResourceRel = "people", path = "people")
  public interface PersonRepository extends PagingAndSortingRepository {
  
    List findByLastName(@Param("name") String name);
    
  }

REST Exception Handling

• Global handling based on Exception types
• See RestResponseEntityExceptionHandler.java

@ControllerAdvice
  public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
      @ExceptionHandler({ Exception.class })
      @ResponseBody
      public ResponseEntity handleAnyException(Exception e) {
          return errorResponse(e, HttpStatus.INTERNAL_SERVER_ERROR);
      }
      
      @ExceptionHandler({ InvocationTargetException.class, IllegalArgumentException.class})
      @ResponseBody
      public ResponseEntity handleMiscFailures(Throwable t) {
          return errorResponse(t, HttpStatus.BAD_REQUEST);
      }
                

Spring MVC Tests  

class AccountControllerTest extends Specification {
  def accountController = new AccountController()
  
  MockMvc mockMvc = standaloneSetup(accountController).build()
  
  def "getAccount test hits the URL and parses JSON output"() {
      when: 'rest account url is hit'
      def response = mockMvc.perform(get('/rest/account')).andReturn().response
      def content = new JsonSlurper().parseText(response.contentAsString)
      
      then: 'securityService correctly returned account in JSON'
      response.status == OK.value()
      
      //Can test the whole content string that is returned
      response.contentAsString == '{"username":"spockUser"}'
      
      //Or can use the JsonSlurper version to test the JSON as object
      content.username == 'spockUser'
  }
}

Much more

• JSP/GSP/Thymeleaf
• Metrics - app-server style
• No-SQL data stores, if that's your thing
• Great docs
• Simple tutorials

Old + New = Spring Boot

JHipster!  

• Opinionated AngularJS + Spring Boot
• Yeoman, Grunt, Bower, Gradle
• Karma Client-side tests
• Liquibase data bootstrapping
• Thymeleaf, Hazelcast, Logback, HikariCP
• Websockets with Atmosphere

Community & Branding

• It starts with an image
• Plus, the developers are amazing people
• The project is fun and positive
• Exhibit A: Response to Comic-Sans bug
• Julien Dubois @juliendubois
• Jérôme Mirc @JeromeMirc

Code Generation?

• Yeoman generates a jumpstarted app
• Also Grails-like entity generators
• Personally, I use it to build up an app structure
• At a minimum, generate an app and borrow ideas
• Can 'update' from JHipster updates, but YMMV
• vs Maven Archetypes

Slides!

• So cool they provide their own slides
• and they're much cooler than mine
• so I borrowed the next few slides from them
• Launch

JHipster Goals

• A beautiful front-end
• Latest HTML5/CSS3/JavaScript frameworks
• Latest Java/Caching/Data access technologies
• With security and performance in mind
• And great developer tooling

High Level

• Client-side
• Server-side

Generate App

npm install -g yo
npm install -g generator-jhipster
yo jhipster
gradle bootRun
grunt server

Code Walk-thru

Entity Generators

yo jhipster:entity location
//city, state, one-to-many attendee

yo jhipster:entity attendee
//name, previousAttendee, notes, many-to-one location

Show and Tell

• Change db to on-disk
• Display city, state on attendee.html list (Livereload!)
• Improve previousAttendee Y/N

JHipster-loaded

• Hot Swap almost any class
• Stop bouncing your app server
• Like JRebel but free! (as in speech AND beer)
• Extension on Spring-loaded (used by Grails)

Dev and Prod profiles

• Dev by default
• Compile or run with -Pprod to use Prod mode
• or an exectuable war:

mvn -Pprod package
java -jar jhipster-0.0.1-SNAPSHOT.war --spring.profiles.active=prod

Extras

• Liquibase
• Metrics screen
• GZipping and HTTP Caching Headers
• ehcache and hazelcast
• Docker container
• Heroku and Openshift deployments

Conclusion

All good? What's not to like?

• Bloat - Downloads the whole internet
• Memory footprint is tough for free cloud deploys
• Treat container support as "beta" (my words)
• I had trouble with Websphere 8.5.5

What about my legacy app?

• Pull in pieces today
• Look at github for Spring Boot
• Generate a JHipster app and look around
• Use Spring Profiles now!
• Java Config!
• Like building Grails from scratch...

Many Many Thanks!

• Bootiful Apps talk by Josh Long
• Exploring Microframeworks by Dan Woods
• JHipster Twitter account @java_hipster