Jeep Cherokee Straight 6 engine?

ive researched around and found that the straight 6 (inline 6) 4.0L engine for jeeps are one of the most reliable engines jeep ever made. im just wondering if all jeep 6 cyl engines are inline 6? like if someone says its 6cyl does that mean it is a straight 6 engine? or are there different types of 6 cyl engines that jeep used? im looking at a 2000 jeep cherokee. thanks