Eclipse: Difference between clean, build and publish

Question

I am using eclipse with tomcat. On the server (right-click)tab you have the options: Clean, Publish and Clean Tomcat Work directory, What do these options really do and how are they different from project > Build

Answer 1

When you run "project > Build" , eclipse will compile all sources in folders on the build path to the .class files and put the .class files into the output folder you specified. Both of these folders can be configured from Project-> Properties-> Java Build Path . Note that eclipse has the incremental build feature that will only compile the sources that have changed since the last time the project is build.

If you enable Auto-build for the project ( via "Project-> Build Automatically" ) , the "project > Build" will run automatically when you add, remove, or modify the source files on the build path , so you don't have to call "project > Build" manually in this case.

The Publish option in the server tab will deploy the application to your Tomcat instance by copying the project resources such as xml configuration files , web resource (html ,css, js etc) , and the compiled .class files you get from the "project > Build" to the correct location of the Tomcat instance .

So , "Project > Build" is about compiling java sources to the .class files while the options in the server tab is about deploying the application to the tomcat instance and maintaining the tomcat instance .

You can find the information about the "server tab" (i.e. Web Tools Platform) from the following links: http://help.eclipse.org/helios/index.jsp?topic=/org.eclipse.wst.server.ui.doc.user/topics/tpublish.html http://wiki.eclipse.org/WTP_Tomcat_FAQ