|Most errors are indicated while you're typing or, in any case, when you save the source, so by paying attention to the markers that will be there, you can solve this kind of errors before running.|
|Often you can fix an error by clicking the marker and double-clicking a suggestion, in this case 'import java.applet.Applet'.|
Clicking a word in your source code and pressing Shift-F2 takes you to the documentation if it can be found : Window, Preferences, Java, Installed JRE's, Edit, etc. as shown in the image. You could point to locally installed documentation instead, btw.
The picture also shows how to install Sun's source code, which makes the help-text-popups a lot more interesting and enables you to explore the glorious inner workings of the standard library.
|Typing a dot following a reference variable presents you with a list of methods, constants and, sometimes, variables to choose from. Typing just a dot implies this.|
|Round brackets trigger info about parameters expected.|
If these last two, known as Content Assist, don't appear automatically, you can try Ctrl-space