Pretty common interview process (HR -> Technical Interview -> HR -> Team meeting). People are pretty nice (at least the ones in Barcelona) but everything sounds a bit hasty, so the whole process can be very fast.
Technical Interview is like any other software dev one. You basically get the usual theoretical questions (data structure, OOP related questions, some basic Java questions like Interfaces, test related questions, security related questions (hashing is fine for example), basic database related questions.
Afterwards you get an 1h exercise on a online notepad. Should be pretty accessible, just a basic leetcode exercise to show that you can use data structures and may mix a bit of like read/write concepts.
You get like a day or two to decide after getting offered a contract