I’ve just installed Eclipse 4.2.0 and also imported all my old programs into it, except that when I run my programs, it pops up with a message saying:
Select what to run:
Ant Build: Launches an Ant Build with default
Ant Build…: Launches an Ant Build and allows it to be configured

This message has never appeared to me before. I wonder if it is because I imported my files incorrectly or something that I forgot to install. Please tell me how I can make it work properly again. Thanks in advance.
Ah! this is an issue I’ve experienced earlier. This tip solved the issue. Here’s How to do it.
Make sure that you’ve built it. Or you can enable
Project --> Build Automatically.After the above option is set, try cleaning the workspace.
Project --> Cleanand clean all the projects you’ve imported.Now
restarteclipse and you can launch your program.