Eclipse doesn't build

Question

A previously working Ecplise now gives me the error

Java Virtual Machine Launcher
Could not find main class: testing2. Program will exist.

testing2 is my class and a source file exists but Ecplise doesn't seem to build the .class file. Maybe I hit the wrong hotkey and changed accidently some setting?

Answer 1

The following menu item should be checked : Project > Build Automatically

Answer 2

As Bozho said Build Automatically should be checked which builds your project on every save of your source file.

If it is unchecked then you have to manually build the project by right clicking on it and select Build Project.