You can use the Desktop class to issue a browser open:
java.net.URI uri = new java.net.URI.create("http://mywebsite.com");
int iBrowserWindows = 5;
for (int i = 0; i < iBrowserWindows; ++i)
catch (java.IO.IOException ex)
Repeat the browse as desired for multiple sites. You could also try an exec, but I wouldn't if the above works.