this.size = size >= MIN_SIZE ? size : MIN_SIZE;
is the shortcut for
 if (size >= MIN_SIZE){
      this.size = size; //i.e. keep it.
 }else{
     this.size = MIN_SIZE;
 }
Or in generic speech:
value = (condition)? optionA : optionB;
equals
if (condition){
   value = optionA;
}else{
   value = optionB;
}
6
solved JAVA: what does this symbols means: ‘>=’, ‘?’ and ‘:’? [closed]