aSearch is a little Search applet that runs on all browser with support JDK 1.1x. With aSearch you can define a list of search engines in a file (group by categories.) and launch your query in the engine. It's a free applet ("Freeware"), and includes full source code.

The K.I.S.S. Java applet allows you to query multiple internet search engines in one single step. Simply enter a search string, select one (or more) search engines, and click on the search button. For each search engine you selected the applet will then display the results in a new window.