No, GameMaker does not use Java for its game development process. GameMaker Studio, developed by YoYo Games, utilizes its own scripting language called GameMaker Language (GML). GML is a C-like language specifically designed to be used within the GameMaker environment.
For example, if you want to move an object in GameMaker, you might write code like this:
This GML code checks for keyboard input and moves the object accordingly along the x-axis. You won't find Java syntax or semantics here because GML is optimized for GameMaker's ecosystem.
However, for those curious about integrating Java with GameMaker, it's theoretically possible to interface with Java programs using extensions or DLLs, but this would require advanced knowledge and isn't a common practice when working with GameMaker Studio.