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Advanced Java Programming Technique
Target
AD212: Advanced Techniques for
Java Programming in Lotus Notes
and Lotus Domino
Wai-Ki Yip
Manager and Project Leader
Language Services
Audience
–Some Java knowledge
–Some experience programming Java in Notes/Domino
Purpose
–Provide detail technical information
–Explain what happens behind the scene
Result
–Answer some questions
–Write better Java programs
Keith Kimball
Software Engineer
Agenda
JRE Versions
JRE
The
Versions
Customization using NOTES.INI Variables
Domino Objects and Memory Management
Accessing Domino Classes from a Java main program
JVM
–Local access
–Remote access
Additional
Packages
Installing a Java Extension
Intersection of Java and Notes Security
Trouble Shooting Tips
JRE is packaged and shipped with Notes/Domino or it is
installed as part of the Operating System
–Tested thoroughly
–Should just work
–In most cases, you don't have to worry about it.
Notes/Domino
Notes/Domino
5 - JRE 1.1.8
6 - JRE 1.3.1
1
Notes/Domino 5
JDK
Notes/Domino 6
1.1.6 in early releases, 1.1.8 by now
Platform
Version
Win32
JDK 1.3.1 (IBM)
Solaris
JRE 1.3.1 (Sun)
LINUX
JRE 1.3.1 (IBM)
JRE 1.1.8 (IBM)
AIX
JRE 1.3.1 (IBM)
JDK 1.1.8 (IBM)
AS/400 (iSeries)
JDK 1.3.1 (IBM)
OS/2
not applicable
OS/390 (zSeries)
JDK 1.3.1 (IBM)
HPUX
not applicable
MAC OS/9
MRJ 1.2/JDK 1.1.8 (Apple)
Platform
Version
Win32
JDK 1.1.8 (Sun)
Solaris
JRE 1.1.8 (Sun)
Linux
JRE 1.1.8 (Sun)
AIX
AS/400 (iSeries)
OS/2
JRE 1.1.8 (IBM)
OS/390 (zSeries)
JDK 1.1.8 (IBM)
HPUX
JRE 1.1.6 -> JRE 1.1.8 (HP)
MAC
(mostly 1.3.1)
no support
JRE - Java Runtime Environment
JDK - Java Development Kit
Changes from ND5 to ND6
Importance of Java Releases/Versions
JRE
Increased
1.1.8
->
JRE 1.3.1
–skipped JRE 1.2 and JRE 1.3.0
Sun
->
IBM
functionality
performance and scalability
Java Releases are like Operating System releases
Better
–Win32, LINUX
–changed implementation (Sun to IBM)
–the underlying JVMs are actually quite different
–changed internally
–deprecated APIs
2
What Lotus Does With the New Release ?
Don't Recommend Change JVM Yourself
Work
to make sure it functions properly in Notes/Domino
Certain
–Rebuild all our Java code
Other
–Test existing and new functionality
features may fail
subtle problems
–Performance
–Monitor any performance/scalability, memory consumption
–Scalability
characteristics change
–Memory consumption
–Accommodate all changes
–Normally, it took us about 3 months of continuous running to notice
deprecate APIs
–directory structure changes
–take advantage of new interfaces
these kind of problems
–
JVM Directory Structure in ND5
JVM Directory Structure in ND6
JVM
A
binaries installed with the other Notes/Domino executables
–c:\Lotus\Notes on the client or
–c:\Lotus\Domino on the server
Core JVM
–Native method libraries used by the core Java classes
–Archives (.jar) containing the JVM core classes
–Subdirectory lib (java.home system property)
–font.properties, awt.properties, etc...
–
complete JRE subtree in the Notes executable directory
–Subdirectory jvm
Content is platform dependent
JVM core libraries, core classes, misc files
–Relative path for its subdirectories
–Bin
–Lib
–
–
3
Do You Need to Know About This ?
Agenda
Difficult
JRE
to replace the 1.1.8 JVM in ND5 with 1.3 or 1.4 JVM
–Need special knowledge about directory structure
–Need to remove all 1.1.8 files. Otherwise, you may running a mixture
of 1.1.8 and 1.3 JVM. You may encounter some very interesting
problems.
Install
Customization using NOTES.INI Variables
Domino
Objects and Memory Management
Domino Classes from a Java main program
Accessing
an extension package
–JSSE 1.0.3_01
Versions
JVM
–local access
–remote access
Additional
Packages
a Java Extension
Intersection of Java and Notes Security
Trouble Shooting Tips
Installing
JVM Customization using NOTES.INI
Variables
JVM Selection INI Variables
JVM
INI
Selection
Stacksize
Classpath
Garbage
collection
Verbose information
Verification
JIT
OS400
variables
–JavaClientVM (-client)
–JavaServerVM (-server)
–JavaHotspotVM (-hotspot)
Example
–JavaClientVM=1
4
Stacksize INI Variables
Classpath INI Variables
INI
INI
Variables
variable
–JavaStackSize (-oss)
–JavaNativeStackSize (-ss)
Size
is number optionally followed by one of
–JavaUserClasses (-classpath)
Note
–Contains a list of directories, jar, and zip files on local disk
–k or K (kilobytes)
–Classes are loaded by System ClassLoader
–m or M (megabytes)
–Loaded classes are “trusted”
Example
–Files on local disk are not replicated
–JavaStackSize=400k
–Consider putting in shared library within Notes
ND5
Restriction
–NOTES.ini variables limited to 256 characters
Example
–JavaUserClasses=c:\domino\data\local;f:\jserv\lib\classes.zip
Garbage Collection INI Variables
Verbose INI Variables
Heapsize
INI
Class
INI variables
variables
–JavaMinHeapSize (-ms)
–JavaVerbose (-verbose:class)
–JavaMaxHeapSize (-mx)
–JavaVerboseGC (-verbose:gc)
collection INI variable
–JavaNoClassGC (-noclassgc)
–JavaNoAsyncGC (JRE 1.1.8 Only)
Examples
–JavaMaxHeapSize=256m
–JavaNoClassGC=1
–JavaVerboseJNI (-verbose:jni)
Verbose
output about
–classes loaded and each source files compiled
–garbage collection events
–use of native methods
Example
–JavaVerbose=1
5
Verification INI Variables
JIT INI Variables
INI
INI
Variables
Variables
–JavaNoVerify (-noverify)
–JavaEnableJIT
–JavaVerify (-verify)
–JavaDisableJIT
–JavaVerifyRemote (-verifyremote)
Example
–JavaJITName
Example
–JavaEnableJIT=1
–JavaVerify=1
OS400 INI Variables
Agenda
JavaOS400LoadLib
JRE
JavaOS400Optimize
JVM
JavaOS400CHKPATH
Domino
Objects and Memory Management
JavaOS400RegisterNatives
Accessing
Domino Classes from a Java main program
JavaUserClassesExt
Versions
Customization using NOTES.INI Variables
–local access
–remote access
Additional
Packages
a Java Extension
Intersection of Java and Notes Security
Trouble Shooting Tips
Installing
6
Domino Objects and Memory Management
Domino Objects & Memory Management
after recycle( )
parent
parent
Java
Object
Java
Object
Java
Heap
Java
Heap
C++
Object
BackEnd
Heap
BackEnd
Heap
Domino Objects & Memory Management
Memory Management Web Agents & Servlets
recycle(
Agents
)
–destroys Back End objects
–Small agents are easy
–Java wrappers visible to GC
Do
it yourself
–leave only crumbs for GC
–Larger agents need help
Servlets
Have
must be managed
a plan!
7
Web Agents Must Keep a Small Footprint
Servlets & Long-Running Agents
Servlets
–Use message handler structure
–Create Session for each Request
doGet( )
Session.recycle( ) when finished
–doPost( )
–fully consider data contention
–
–
Agents
less obvious
–Agent owns the Session
–Examine structure
–
Raising the Bar: Multithreading
capitalize on opportunities to clean up
Multithreading
Design
must be carefully done
management more involved
Debugging difficult
No win for CPU bound tasks
Efficient for heavy I/O tasks
Memory
8
Multithreading Domino Objects
Multithreading - Notes on Backend
Architecture
All
Within
D.O. threads must be registered
a Session
–sInitThread( )
–Objects shared across threads
–sTermThread( )
–Methods are synchronized
–AWT event handlers
NotesThread
will do this for you
Controlling thread must be kept alive
–Parents must be preserved
–Containment model is important
–Use DbDirectory on only one thread
Across
Sessions
–Objects are independent
–Data contention possible
Profile
–join( ) is helpful
Documents cached per thread
–Last one in wins!
Multithreading - Memory management
R5 Vs R6 Memory Management
Recycled
R6
Be
Use
object unavailable to any thread
aware of parent/child relationships
Documents serve many masters
–Item access
–Collection member
–Best to design these situations out
Architecture is more GC/Robust
R5 rules for backwards compatibility
–Recycle!
R6
more flexible for complex situations
GC remains lazy
DB
access OK from any thread
recycle Database on opening thread
9
Agenda
Environment Setup for Java Main Program
accessing local Domino Classes
JRE
Add
Notes.jar to CLASSPATH
Add
directory to PATH
Versions
Customization using NOTES.INI Variables
Domino Objects and Memory Management
JVM
Accessing
program
Domino Classes from a Java main
–Set CLASSPATH=.;C:\Lotus\Notes\Notes.jar
–Set PATH=%PATH%;C:\Lotus\Notes
Alternative:
use java's and javac's–classpath option
–local access
–remote access
Additional
Packages
a Java Extension
Intersection of Java and Notes Security
Trouble Shooting Tips
Installing
Java and Javac Commands
Local Access to Domino Classes
Use
3
java command shipped with Notes located in jvm\bin in
program directory.
–c:\lotus\notes\jvm\bin\java JavaMain
Javac
command not shipped with Notes.
–Use version on system
Choices
–Extend NotesThread class
–Implement Runable Interface
–Static NotesThread method
Important
Concept:
–Domino must be aware of threads using classes
10
Extend NotesThread Class
import lotus.domino.*;
public class JavaMain1 extends NotesThread {
public static void main(String a[]){
JavaMain1 t = new JavaMain1();
t.start();
}
public void runNotes(){
try {
Session s = NotesFactory.createSession();
String p = s.getPlatform());
System.out.println("Platform = " + p);
} catch (Exception e){}
}
}
Static NotesThread Method
import lotus.domino.*;
public class JavaMain3 {
public static void main(String a[]){
try {
NotesThread.sinitThread();
Session s = NotesFactory.createSession();
String p = s.getPlatform());
System.out.println("Platform = " + p);
} catch (Exception e) {
} finally { NotesThread.stermThread();}
}
}
Implement Runnable Interface
import lotus.domino.*;
public class JavaMain2 implements Runnable {
public static void main(String a[]){
JavaMain2 t = new JavaMain2();
NotesThread nt = new NotesThread((Runnable)t);
nt.start();
}
public void run(){
try {
Session s = NotesFactory.createSession();
String p = s.getPlatform());
System.out.println("Platform = " + p);
} catch (Exception e){}
}
}
Key Concepts
Establish
environment
Javac command from System
Use Java command from Notes
Use one of the suggested approaches
Use
11
Remote Access to Domino Classes
Don't
use NotesThread
CORBA usage
Only need NSCO.jar on remote machine
Transparent
–Location: C:\Lotus\{notes or domino}\Data\domino\java\NSCO.jar
–Put on CLASSPATH
Hint:
ALLOW_NOTES_PACKAGE_APPLETS=1 if using applets
must be running http and diiop
Following example:
Server
–java JavaRemote myserver.ibm.com user password
Remote Access to Domino Classes
import lotus.domino.*;
public class JavaRemote {
public static void main(String argv[]) {
try {
String host = argv[0],
user = argv[1],
pwd = argv[2];
Session s = NotesFactory.createSession
(host, user, pwd);
System.out.print(s.getPlatform());
} catch (Exception e) {
e.printStackTrace();
}
}}
Agenda
Java Packages
JRE
JavaMail
Versions
Customization using NOTES.INI Variables
Domino Objects and Memory Management
Accessing Domino Classes from a Java main program
–Imap.jar
–Mail.jar
–Mailapi.jar
–local access
–Pop3.jar
–remote access
Additional
–Smtp.jar
Packages
Installing a Java Extension
JavaHelp
Intersection
XML
Trouble
of Java and Notes Security
Shooting Tips
(Sun)
–Activation.jar
JVM
(Sun)
–Jhall.jar
(Apache)
–LotusXSL.jar (Xalan)
–XML4J.jar (Xerces)
–See other sessions
12
Using Java Extensions
Adding JSSE Java Extension
HTTP
vs HTTPS
Download
–http - net package
Shutdown
–https - security package
JRE
1.3.1 does not officially support https
–Sun does provide an extension package
–need to install into the jvm subdirectory
JRE
1.4 will support https
Agenda
JSSE 1.0.3_01 from Sun website
notes
Install the JSSE jar files into <program_directory>\jvm\lib\ext\
Package specific operations (from INSTALL.txt)
–Edit <program_directory>\jvm\lib\security\java.security
Restart
Test
Notes
Installation
Applet Security (File->Preferences->User Preferences)
JRE
Versions
Customization using NOTES.INI Variables
Domino Objects and Memory Management
Accessing Domino Classes from a Java main program
JVM
–local access
–remote access
Additional
Installing
Packages
a Java Extension
Intersection
Trouble
of Java and Notes Security
Shooting Tips
13
Applet Security (File->Security->User Security)
Workstation Security (File->Security->User Security)
Workstation to Java Security
Workstation to Java Security (Cont)
14
Server Restricted Access
Agenda
checkAccept
checkMemberAccess
JRE
checkAccess
checkMulticast
JVM
checkConnect
checkPackageDefinition
checkCreateClassLoader
checkPropertiesAccess
checkDelete
checkPropertyAccess
checkExec
checkRead
checkExit
checkSetFactory
checkLink
checkWrite
checkListen
Versions
Customization using NOTES.INI Variables
Domino Objects and Memory Management
Accessing Domino Classes from a Java main program
–local access
–remote access
Additional
Packages
a Java Extension
Intersection of Java and Notes Security
Installing
Trouble
Shooting Tips
Trouble Shooting Tip #1
Trouble Shooting Tip #2
requires
Check
a minimum of 256 color on the monitor
–not an issue with client but usually people throw in a cheap monitor
(16 color) for the server
–java won't start as a result
which platform it does not have support
–ND 6 uses IBM's 1.3.1 which does not run on Win95
–no support on MAC OS/X yet
–later version of ND5 and ND6 will raise an exception.
15
Trouble Shooting Tip #3
Trouble Shooting Tip #4
Don't
There
catch thread death exception in your code
–For java agent, we created a thread group
create 3 threads
–agent loader - load the agent
–agent launcher - launch the agent
–timer thread to check for time out and control break
–threadgroup.kill
–raise a thread death exception to each of its threads
–catching thread death and continue will make your agent not
terminable
–
Resources
is no general way of limiting the resources that Java
uses.
Don't rely on Java Garbage Collector for efficient memory
consumption in Notes/Domino.
Use recycle
Questions?
www.java.sun.com
www.ibm.com/java
www.apache.org
www.notes.net
www.lotus.com
?
16
