What do the icons in Eclipse mean?

Question

What do the icons in the Eclipse debugger mean?
What do the icons in Eclipse's Package Explorer mean?
What do the little letters on top of Eclipse icons mean?
What's the difference between the two error icons in Eclipse (the x in the red circle and the one with the light bulb)?

I just came to SO looking for this, didn't find it, and found it on my own elsewhere. But I thought it would be good for SO to have the answer for future reference; I wondered about them all the time when I was new to Eclipse (this was before I discovered SO). This post is community wiki, because people like different amounts of detail in their explanations and so it doesn't start a "you're fishing for rep" war.

Answer 1

This is a fairly comprehensive list from the Eclipse documentation. If anyone knows of another list -- maybe with more details, or just the most common icons -- feel free to add it.

http://help.eclipse.org/galileo/topic/org.eclipse.jdt.doc.user/reference/ref-icons.htm?resultof=%22icon%22

There are also some CDT icons at the bottom of this help page.

Answer 2

It will be easy to answer if you attach icons with them. Eclipse is a very powerful tool but it will bugs you a lot in starting but when you adjust in Eclipse environment ... you will enjoy it.

The light bulb appears when Eclipse suggest some action to you, like generation a stub for your method or attach auto generated UUID with the class and etc