eclipse builds all projects even on issuing build for single project

Question

There seems to be some issue with Eclipse VERSION 3.7

When I compile some single project ( though ant or though buildProject) , Eclipse starts building all projects in workspace and that takes a long amount of time.

I have tried building project in two ways -

1. right click ant file, select Run as And Build

2. Right Click project in Eclipse , select Build Project.

Both ways Eclipse starts building other open projects first.

is there any ways we can avoid it.

Answer 1

Three options I can think of:

1. Disable automatic building (Preferences->General->Workspace).
2. Change the build order to compile the project you need first (Preferences->General->Workspace->Build Order).
3. Close any projects you don't want built.

None of these is ideal, but they may be an improvement.

Answer 2

I have checked the options you have in the current Eclipse release, Indigo.

• Use automatic building: See the Menu Project > Build Automatically. If that is on, Eclipse builds on its own only when there are changes to files, and it will build incrementally. I suspect that this option is off for you.
• If the option is not used, you can start a build by doing Project > Build All or Project > Build Project. As the menu entries say, only the first one will build all your projects. Perhaps you are using the keybinding that starts that menu entry? CTRL-B? This will only do anything if something has changed.
• When doing a clean build, there comes a popup (see below) with some options in it. If you set the right options, only the project you have selected will be cleaned and then built.

So only the options Clean projects selected below combined with Build only the selected projects will do what you want.

I do not understand why an Ant build (started in Eclipse) of one project will lead to a rebuild of all projects in the same workspace. There is no connection at all from the Ant build to the eclipse projects. The only reason I could imagine is, that the Ant build touches something, which is then dirty, and that leads to a new build. Perhaps you should add information about your build file, the directory structure you work on, ...