./gradlew build

The following instructions have been tested in IDEA 2017.3

Go to Help->Edit Custom Properties... and add the following line:

idea.max.intellisense.filesize=12500

Now close and restart IDEA. This ensures that IDEA will be able to handle Bisq's very large generated PB.java Protobuf sources. Without changing this setting, you will get compilation errors in IDEA wherever these generated types are used.

Go to File->Open... and choose this project's build.gradle file. When prompted whether to overwrite the existing .idea directory, choose "Yes".

In the Project tool window, right click on the .idea folder, select Git->Revert... and click OK in the dialog that appears. Doing this restores source-controlled .idea configuration files that get overwritten during project import.

You should now be able to build the project without errors using Build->Build Project.