'Please understand that hot water for passenger's personal food is not available for safety reasons to prevent burning accidents and for the reason of limited hot water capacity. (However, for milk powder/grain formula for infants/children and the patient, hot water can be provided within the proper cooking temperature.)
Jin Air sells snacks (ramen, coffee, etc.) which are safely handled under careful control.
Please refrain from bringing in food that can significantly degrade the in-flight comfort.