Reloading Java Applications Like A Pro

Transcript

1. reloading java applications like a pro Anton  Arhipov  
2. whoami anton arhipov @antonarhipov jrebel product lead zeroturnaround
3. agenda • the time sink • application updates (with jrebel)
4. make a change build, deploy, wait check the change the turnaround
5. package everything into WAR/EAR rackage modules into JARs compile classes copy static resources resolve dependencies build
6. exploded directory deployment
7. public class Launcher { public static void main(String[] args) { Server server = new Server(); SelectChannelConnector connector = new SelectChannelConnector(); connector.setPort(8080); server.addConnector(connector); WebAppContext context = new WebAppContext("war", "/"); server.setHandler(context); server.start(); } } jetty launcher
8. “…I  know  about  JRebel,  but  I  cannot   pay  for  it,  so  I  tried  Maven…”                                                                                        -­‐  Stackoverflow  
9. getResource(“hello.html”)   read(“src/main/.../hello.html”)  
10. package everything into WAR/EAR rackage modules into JARs compile classes copy static resources resolve dependencies build
11. package everything into WAR/EAR rackage modules into JARs compile classes copy static resources resolve dependencies build
12. no build! • compile with your IDE • prefer exploded deployment • avoid <<mvn clean install>>
13. 1–60s 30s$–$15min ~1min container boot time application deployment navigation redeploy’s time
14. h@p://dow.ngra.de/2010/12/14/jee-­‐oss-­‐container-­‐startup-­‐Jmes-­‐apples-­‐vs-­‐oranges/   container startup time
15. h@p://zeroturnaround.com/java-­‐ee-­‐producJvity-­‐report-­‐2011/  
16. Externalized   Temporary   Serializable   DerivaJve   State   why code reloading is hard?
17. MyObject   MyObject.class   OldClassLoader   NewClassLoader   MyObject.class   MyObject   Recreate  object   naiive class reloading
18. Classes Libraries OldClassLoader NewClassLoader Sevlet New Classes New Libraries Sevlet Session Session init()   App State App State serialize/deserialize
19. Classes OldClassLoader NewClassLoader Sevlet New Classes New Libraries Sevlet Session Session App State App State
20. MyObject MyObject.class   OldClassLoader Code   101000101   100010010   Debugger HotSwap   New  code   111000100   101010010   New  code   111000100   101010010   hotswap Make  changes  
21. MyObject MyObject.class   OldClassLoader Code   101000101   100010010   New  code   111000100   101010010   JRebel   Framework   ConfiguraJon   (XML,  annotaJons,..)   jrebel Make  changes  
22. HotSwap   JRebel   Changing  method  bodies   +   +   Adding/removing  methods   -­‐   +   Adding/removing  constructors   -­‐   +   Adding/removing  fields   -­‐   +   Adding/removing  classes   -­‐   +   Adding/removing  annotaJons   -­‐   +   Replacing  superclass   -­‐   -­‐   Adding/removing  implemented   interfaces   -­‐   -­‐   jrebel vs hotswap
23. in action
24. Java App Framework Conf XML HTTP request
25. Java App Framework Conf XML HTTP request 1) Stop request
26. Java App Framework Conf XML HTTP request 2) Check resources
27. Java App Framework Conf XML HTTP request 3) Reconfigure the framework
28. Java App Framework Conf XML HTTP request 4) Resume request
29. Java App Framework Conf XML HTTP request PROFIT! J
30. Java App Framework Conf XML HTTP request OpJonally:   File  system     PUSH  
32. application reloading is hard • requires more than just class reloading • reloading of different components should appear in particular order • bootstrapping
33. with java ee
34. jrebel for java ee • JSP • JAX-RS • JAX-WS • JSF • CDI • JPA • EJB • Jasper • Jersey, CXF • Metro • Mojarra, MyFaces • Weld • EclipseLink, OpenJPA, Hibernate
35. goes cloud
36. Remote Deployments • Development servers • Virtualized environments • Cloud environments
37. Remote Deployments 0. make a change 1. git commit; git push 2. mvn clean install 3. deploy.sh
38. 0. make a change 1. compile 2. synch & reload
39. h@p://bit.ly/33degree2013     win a free license
40. Questions? @antonarhipov anton@zeroturnaround.com