servlet&jsp puml

request-response.dot

@startdot
digraph foo {
  container [shape=box]
  servlet [fillcolor=grey, style="filled", shape=hexagon]
  clientA [shape=box, color=gray58, style="filled"]
  clientB [shape=box, color=gray58, style="filled"]
  threadA [shape=ellipse, color=gray90, style="filled"]
  threadB [shape=ellipse, color=gray90, style="filled"]
  response1 [shape=point]
  request1 [shape=point]
  request2 [shape=point]
  response2 [shape=point]
  clientA -> container
  clientB -> container
  clientA -> servlet [style=invis]
  clientB -> servlet [style=invis]
  container -> servlet
  servlet -> threadA
  servlet -> threadB
  threadA -> response1 [arrowhead="none", headlabel="response"]
  response1 -> clientA [style="dashed", arrowhead="vee"]
  threadA -> request1 [arrowhead="none", headlabel="request"]
  threadB -> request2 [arrowhead="none", headlabel="request"]
  threadB -> response2 [arrowhead="none", headlabel="response"]
  response2 -> clientB [style="dashed", arrowhead="vee"]

  overlap=false
}
@enddot

servlet-lifecycle-1.puml

@startuml
skinparam state {
  StartColor MediumBlue
  EndColor Red
  BackgroundColor<<1>> Olive
  BorderColor Gray
}
state "does not exist" as NotExist <<1>>
state "initialized" as Initialized <<1>>
[*] --> NotExist
NotExist --> [*]
NotExist -> Initialized : constructor init()
Initialized -> Initialized : service
Initialized -> NotExist : destory
@enduml

servlet-lifecycle-2.puml

@startuml
hide footbox
participant "Web Container" as container
participant "Servlet Class" as class
participant "Servlet Object" as object

create class
container -> class : Load class

create object
container -> object : Instantiate servlet(constructor runs)

container -> object : init()
note right: called only once

container -> object : service()
note right: handle client requests

container -> object : destroy()
@enduml

servlet.http.puml

@startuml
namespace javax.servlet {
  interface Servlet
  abstract class GenericServlet
  Servlet <|-- GenericServlet
  interface ServletRequest
  interface ServletResponse
}
namespace javax.servlet.http {
  abstract class HttpServlet {
    #void service(HttpServletRequest request, HttpServletResponse response)
  }
  javax.servlet.GenericServlet <|-- HttpServlet
  interface HttpServletRequest
  javax.servlet.ServletRequest <|- HttpServletRequest
  interface HttpServletResponse
  javax.servlet.ServletResponse <|- HttpServletResponse
  interface HttpSession
  class Cookie
}
@enduml

servlet.puml

@startuml
namespace javax.servlet {
  interface Servlet {
    void init(ServletConfig config)
    void service(ServletRequest request, ServletResponse response)
    void destroy()
  }
  abstract class GenericServlet
  Servlet <|-- GenericServlet
  interface ServletRequest
  interface ServletResponse
  interface SerlvetContext
  interface ServletConfig
  interface RequestDispatcher
  interface Filter
}
@enduml