(C J) Concave without any line, mole or scar,

 on the other hand , a flat cj means... 

 the person is not a good drinker.

 

The presence of defects such as lines, moles, or wounds on the C.J,

indicate... 

the person suffers from frequent digestive problems, such as allergies and food poisoning.

 

 You should pay special attention to the color of the C.J. while traveling abroad because the presence of any dark, grey, black or green color in the C.J., 

means... the person is likely to have digestive problems even though the C.J. is concave and perfect. 

Such a color is a negative indication of the possibility of food poisoning.