It felt like something, but I just forgot. Picture is truth, look at the answers on stack overflow.

So this step removes the class files that have been compiled in the project and recompiles them. That’s all. What’s the difference between
and build all, since eclipse builds on
The time stamp
Of the judgment mechanism. So when you press build all some classes that eclipse thinks the timestamp hasn’t changed won’t be recompiled.
I’m sure you know the difference between Clean and Build All.