Both texts are no doubt correct it is most likely that one of jesses sons died before making any significant impact during davids reign thus being of no account to the chronicler you will note that 1 chronicles 213 15 does not state that jesse only ever had seven sons it simply names seven of his sons including david and two of his daughters. Either jesse had eight sons or he had seven if someone has eight kids and one dies you dont say oh she only had seven kids you say she had eight but one of them died besides if youre writing 600 years in the future as uk apologetics suggests they all died whether they had kids is irrelevant. And he said there remaineth yet the youngest and behold he keepeth the sheep and samuel said unto jesse send and fetch him for we will not sit down till he come hither the above passage says that jesse had seven sons plus david or eight sons total chapter 17 verse 12 confirms that jesse had eight sons. At that moment jesse had eight sons as is clearly stated in chapter 1610 11 and 1712 in 1 chronicles we read an enumeration of jesses sons seven in number however this list is of much later date representing the descendants of patriarch judah