I am getting error SEVERE: java.lang.UnsatisfiedLinkError: no j3dcore-ogl-chk in java.library.path when I am trying to run Applet.
Do any one have any idea.

Give us more information on what libraries are you trying to use in that applet and what platform are you trying to run this on. I have a strong **feeling** you are not on windows or not using the Sun JRE (of course I could be wrong).

I am trying to access java3d library in applet. They are actully dll files. when I am runnig it through eclipse it works fine but when I am trying to run through HTML over the web it is giving me above mentioned error. I am trying to view HTML on Windows with SUN JRE.

You must be having a folder in which you have some dll file . j3dcore-ogl-chk should be one of them

try this code
String path = System.getProperty("java.library.path");

you will get the folders which are visible to java , paste the dlls in any one of these folders .

Worked for me