Spring Framework 4.0 - The Next Generation - Soft-Shake 2013
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Transcript of Spring Framework 4.0 - The Next Generation - Soft-Shake 2013
Spring Framework 4.0 The Next Generation Sam Brannen @sam_brannen
Soft-Shake | Geneva, Switzerland | 24 October 2013
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Sam Brannen
• Spring and Java Consultant @ Swiftmind
• Java Developer for over 15 years
• Spring Framework Core Committer since 2007
• Spring Trainer • Presenter on Spring, Java, OSGi, and testing
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Swiftmind
Your experts for Enterprise Java Areas of expertise • Spring * • Java EE • OSGi • Agile Methodologies • Software Engineering Best Practices
Where you find us • Zurich, Switzerland • Twitter: @swiftmind • http://www.swiftmind.com
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A Show of Hands…
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Agenda
• Spring 3.x in Review
• Themes in 4.0
• Java EE
• Java SE
• Spring 4 on Java 8
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Spring 3.x in Review
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Spring 3.x: Component Model
• Powerful annotated component model – stereotypes, configuration classes, composable
annotations, profiles
• Spring Expression Language (SpEL) – XML config files – @Value, @Cacheable, etc. – JSPs
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Spring 3.x: Component Model
• Comprehensive REST support – and other Spring @MVC additions
• Support for async MVC processing – Spring MVC interacting with Servlet 3.0 async
callbacks
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Spring 3.x: Component Model
• Declarative validation and formatting – integration with JSR-303 Bean Validation
• Declarative scheduling – trigger abstraction and cron support
• Declarative caching – in-memory, Ehcache, etc.
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Spring 3.x: Testing
• Embedded databases via <jdbc /> namespace
• @Configuration classes & @ActiveProfiles
• @WebAppConfiguration
• @ContextHierarchy
• Spring MVC Test framework
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Spring 3.x: Key Specs
• JSR-330 – Dependency Injection for Java – @Inject, @Qualifier, Provider mechanism
• JSR-303 – Bean Validation 1.0 – declarative constraints – embedded validation engine
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Spring 3.x: Key Specs
• JPA 2.0 – persistence provider integration – Spring transactions
• Servlet 3.0 – web.xml-free deployment – async request processing
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Typical Annotated Component
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Composable Stereotypes
• Combining meta-annotations on a custom stereotype • Automatically detected: no configuration necessary!
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Configuration Classes
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Spring 4.0 Themes
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New Baselines
• Java SE 6+
• Java EE 6+ – Servlet 3.0 focused, Servlet 2.5 compatible
• All deprecated packages removed
• Many deprecated methods removed as well
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Third Party Libraries
• Minimum versions ~ mid 2010 now
• For example – Hibernate 3.6+ – Quartz 1.8+ – Ehcache 2.1+
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Java 8 Language and API Features
• Lambda expressions
• Method references
• JSR-310 Date and Time
• Repeatable annotations
• Parameter name discovery
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Groovy + Spring 4.0
• A smooth out-of-the-box experience for Groovy-based Spring applications
• AOP adaptations – special handling of GroovyObject calls – consider a Spring application with all components
written in the Groovy language instead of Java
• Groovy-based bean definitions – formerly known as the Bean Builder in Grails – now to live alongside Spring's configuration class
model
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Conditional Bean Definitions
• A generalized model for conditional bean definitions – a more flexible and more dynamic variant of bean
definition profiles (as known from Spring 3.1) – can be used for smart defaulting – see Spring Boot J
• @Conditional with programmatic Condition implementations – can react to rich context (existing bean definitions,
etc.) – profile support now simply a ProfileCondition
implementation class
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Annotation-based Components
• Custom annotations may override specific attributes of meta-annotations
• Purely convention-based – use of same attribute name
@MyTransactional(readOnly = true)@MySessionScope(scopedProxyMode = TARGET_CLASS)
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Lazy Resolution Proxies
• @Lazy on injection point
• Alternative to Provider<MyTargetType>
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Ordered Injection of Lists & Arrays
• Ordered / @Order on candidate beans
• Relative order within specific injection result
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DI and Generics
• Type matching based on full generic type – e.g., MyRepository<Customer>
• Generic factory methods now fully supported in XML config files – Mockito, EasyMock, etc.
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spring-messaging
• New org.springframework.messaging module
• Extracted from Spring Integration
• Core message and channel abstractions
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WebSockets
• WebSocket endpoint model along the lines of Spring MVC
• JSR-356 but also covering SockJS and STOMP
• Endpoints using generic messaging patterns
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AsyncRestTemplate
• Analogous to existing RestTemplate
• Based on ListenableFuture return values
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Spring and Java EE
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Java EE Support (1/2)
• Spring 2.5 – completed Java EE 5 support – J2EE 1.3 à Java EE 5
• Spring 3.0 – introduced Java EE 6 support – J2EE 1.4 à Java EE 6
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Java EE Support (2/2)
• Spring 3.1 / 3.2 – strong Servlet 3.0 focus – J2EE 1.4 (deprecated) à Java EE 6
• Spring 4.0 – introduces explicit Java EE 7 support – Java EE 5 (with JPA 2.0 feature pack) à Java EE 7
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Enterprise API Updates
• JMS 2.0 – delivery delay, JMS 2.0 createSession() variants, etc.
• JTA 1.2 – javax.transaction.Transactional annotation
• JPA 2.1 – unsynchronized persistence contexts
• Bean Validation 1.1 – method parameter and return value constraints
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Spring and Java SE
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Java SE Support (1/2)
• Spring 2.5 – introduced Java 6 support – JDK 1.4 à JDK 6
• Spring 3.0 – raised the bar to Java 5+ – JDK 5 à JDK 6
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Java SE Support (2/2)
• Spring 3.1 / 3.2 – explicit Java 7 support – JDK 5 à JDK 7
• Spring 4.0 – introduces explicit Java 8 support – JDK 6 à JDK 8
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Java 8 Programming Model
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The State of Java 8
• Delayed again...
• Scheduled for GA in September 2013
• Now just Developer Preview in September
• OpenJDK 8 GA as late as March 2014 L
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IDE Support for Java 8
• IntelliJ – available since IDEA 12, released in Dec 2012
• Eclipse – announced for June 2014 L
• Spring Tool Suite – Eclipse-based beta support earlier
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Java 8 Bytecode Level
• Generated by -target 1.8– compiler's default
• Not accepted by ASM 4.x – Spring's bytecode parsing library
• Spring Framework 4.0 comes with a patched (jarjar’ed) ASM 4.1 variant
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HashMap / HashSet Differences
• Different hash algorithms in use
• Leading to different hash iteration order
• Code shouldn't rely on such an order but sometimes does
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Java 8 Lambda Conventions
Simple rule: interface with single method
– typically callback interfaces
– for example: Runnable, Callable
– formerly “Single Abstract Method” (SAM) types
– now “functional interfaces”
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Lambda + Spring = Natural Fit
Many Spring APIs are candidates for lambdas
– by naturally following the lambda interface conventions
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Lambdas with JmsTemplate
MessageCreator
Message createMessage(Session session)throws JMSException
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Lambdas with TransactionTemplate
TransactionCallback
Object doInTransaction(TransactionStatus status)
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Lambdas with JdbcTemplate
RowMapper
Object mapRow(ResultSet rs, int rowNum)throws SQLException
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Ex: Lambdas with JdbcTemplate #1
JdbcTemplate jt = new JdbcTemplate(dataSource);
jt.query( "SELECT name, age FROM person WHERE dep = ?", ps -> { ps.setString(1, "Sales"); }, (rs, rowNum) -> new Person(rs.getString(1), rs.getInt(2)));
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Ex: Lambdas with JdbcTemplate #2
JdbcTemplate jt = new JdbcTemplate(dataSource);jt.query( "SELECT name, age FROM person WHERE dep = ?", ps -> { ps.setString(1, "Sales"); }, (rs, rowNum) -> { return new Person(rs.getString(1), rs.getInt(2)); });
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Method References
public List<Person> getPersonList(String department) { JdbcTemplate jt = new JdbcTemplate(dataSource); return jt.query( "SELECT name, age FROM person WHERE dep = ?", ps -> { ps.setString(1, "Sales"); }, this::mapPerson);}private Person mapPerson(ResultSet rs, int rowNum) throws SQLException { return new Person(rs.getString(1), rs.getInt(2));}
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JSR-310 Date and Time
import java.time.*;import org.springframework.format.annotation.*;public class Customer { // @DateTimeFormat(iso=ISO.DATE) private LocalDate birthDate; @DateTimeFormat(pattern="M/d/yy h:mm") private LocalDateTime lastContact; // ...}
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Repeatable Annotations
@Scheduled(cron = "0 0 12 * * ?")@Scheduled(cron = "0 0 18 * * ?")public void performTempFileCleanup() { /* ... */ }@Schedules({ @Scheduled(cron = "0 0 12 * * ?"), @Scheduled(cron = "0 0 18 * * ?")})public void performTempFileCleanup() { /* ... */ }
JDK 8
JDK 6+
Container
Repeated
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Parameter Name Discovery
• Java 8 defines a Parameter reflection type for methods – application sources to be compiled with –parameters
• Spring's StandardReflectionParameterNameDiscoverer– reading parameter names via Java 8's new Parameter
type
• Spring's DefaultParameterNameDiscoverer– now checking Java 8 first (-parameters) – ASM-based reading of debug symbols next (-debug)
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In Closing…
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Spring Framework 4.0 Roadmap
• RC1: end of October
• RC2: mid November
• GA: end of 2013
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Upgrade Considerations
• Spring 3.2 does not support 1.8 bytecode level – upgrade to Spring 4.0 to enable Java 8 language
features
• Spring Framework 4.0 still compatible with JDK 6 and 7
• Spring Framework 3.2 is in maintenance mode
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Acknowledgements
Special thanks to Spring Framework project lead Juergen Hoeller for permitting reuse of his content.
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Spring Resources
• Spring Framework – http://projects.spring.io/spring-framework
• Spring Forums – http://forum.spring.io
• Spring JIRA – https://jira.springsource.org
• Spring on GitHub – https://github.com/spring-projects/spring-framework
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Blogs
• Swiftmind Blog – http://www.swiftmind.com/blog
• Spring Blog – http://spring.io/blog
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Q & A
Sam Brannen twitter: @sam_brannen www.slideshare.net/sbrannen www.swiftmind.com