I WANT TO INCLUDE BOOTSTRAP TEMPLATE AT HEADER IS THERE ANY POSSIBILITY ...SUGGESTIONS PLEASE ...

You accidentally kept the "caps lock" key on - don't do that, it makes you come across as shouting (which I'm sure is not what you intended to do).

I'm not sure what Bootstrap integration entails, but there should be no difficulty including additional JS and CSS files. The header file (header.htm) already includes several CSS and JS files, at least one conditionally based on the value of some Java variable.

where i have to place the css,jsand images .....

${contextPath}/templates/${templateName}/js/sss.js

is this the correct format to access the js files?

Yup, templates/${templateName}/js, templates/${templateName}/styles and templates/${templateName}/images are where you would put additional image, CSS and JS files. The value of "templateName" is generally "default".

i want to include a bootstrap template give me some suggestions

What specific problem are you facing that prevents you from integrating it? I don't know Bootstrap, so can't help with the particulars of what needs to be done. But if you have gotten Bootstrap to run in some other Java web app, it shouldn't be hard to integrate it into JForum as well.