Intellij IDEA How to build project automatically

By default, Intellij IDEA doesn’t compile classes automatically. But, you can enable the auto compile feature by following steps :

1. In “Project settings or preferences”
2. Select “Build, Execution, Deployment -> Compiler”
3. Checked Make project automatically

P.S This feature is available since IDEA 12

References

1. Brand New Compiler Mode in IntelliJ IDEA 12