where can i get "Api JavaDoc For rtc 4.0 "

This is pretty much what I can offer. There is a lot of information in the Wiki too. Here some additional links:

https://jazz.net/wiki/bin/view/Main/RtcSdk30

Browse the Plain Java Client Libraries API Javadoc

Use the PDE to search in the SDK, select a class in the code or the Extension point editor, search for references and implementations, search for extension points and their usage and open the specification.

You can jump to declarations and search for references to the API in the SDK
–The SDK provides source code with attached documentation
–The references, especially to the JUnit tests provided with the SDK, show how the API is used in the product

Use Plugin Spy
http://ryehle.wordpress.com/2011/11/21/finding-the-right-service-api-for-your-process-extension/
and other tools to http://marketplace.eclipse.org/content/yet-another-rcp-inspector to look at RTC and how the SDK is used.

Look at https://jazz.net/wiki/bin/view/Main/PreconditionFollowupCreation and more in the Wiki. Search Jazz.net.
You need operation ID's for advisors. See here for what is available: https://jazz.net/wiki/bin/view/Main/CustomPreconditionsTable#operations

Some more links:

https://jazz.net/wiki/bin/view/Main/ProgrammaticLinkCreation
https://jazz.net/wiki/bin/view/Main/RTCSDK20_SourceControl
https://jazz.net/wiki/bin/view/Main/RTCSDK20_ProcessPreConditionExample
https://jazz.net/wiki/bin/view/Main/BuildJavaProgrammingExamples
Build, Approval: https://jazz.net/wiki/bin/view/Main/CustomPreconditionFollowup
https://jazz.net/wiki/bin/view/Main/PreconditionFollowupCreation
SCM, Work Items, Promotion: https://jazz.net/wiki/bin/view/Main/PromotionByWIStatusChange

All the downloads are always on the all downloads tab of the release download: https://jazz.net/downloads/rational-team-concert/releases/4.0?p=allDownloads . This includes SDK, Plain Java Client Libraries and Javadoc for Plain Java.

The Extension workshop https://jazz.net/library/article/634 can help you get started. We are about to publish an update. In the meantime I added some observations to the comments that should help you to set up for 4.0 development by following the 3.0.1 workshop and just taking the comments into consideration.