how to make IDEA build automatically

In the past, I always use eclipse as my main IDE, but after I try to use IDEA, I drop eclipse right away and buy a personal license of IDEA. IDEA has more powerful features than eclipse, compare with IDEA, eclipse just like a simple toy.

When you first time try IDEA, you may feel not very good at it, especially for some features you are very familiar with them in eclipse. Don't worry about it, just try to find them. Everything you can find in eclipse, you can find new one to replace it in IDEA.

Just like this build automatically feature, when your project is very big and has so many classes, this feature is very important, because it can warn you in error warning window when you have errors in class files. But for the default, it is hidden in IDEA, you need to turn on it by hand. It's very easy, just do like the following figure:

Then the familiar window will display in your front: