NetBeans uses Ant build scripts, and Eclipse lets you create a new project based on an Ant build script, so you could try that. In Eclipse, do File > New > Project, then Java > Java Project From Existing Ant Build.
I never said make a new project from scratch. I said that you can create an Eclipse project based on an Ant script. Doing so will create the necessary constructs within Eclipse so that you can edit your project there. This is like opening the NetBeans project in Eclipse and having Eclipse convert the project into an Eclipse project. Note that there is no way to open a NetBeans project within Eclipse (or the other way around) without going through such a conversion.
Anthony, you are right. Looks like NetBeans build scripts are architected in such a way as to prevent Eclipse from understanding them. Too bad. (Note that I never said I had actually done this, I simply recommended to simranjeet that he(?) try it... )
But this worked for me:
1) create a new Java project and identify the NetBeans project directory as the location
2) identify the Java source directories
3) add an ant builder to the project using the NetBeans build script.