[Adam]

It looks to me like there are a few different situations we need to understand here.

End line throwin, after a made basket. A1, A2, A3, A4, and A5 may all be out of bounds and can play hot potato with the basketball. They get 5 seconds total before it needs to be released onto the court. If A1 releases the ball right before the 5 second count is up, and A2 catches it while still OOB, you have a 5 second violation.

2. End line throwin. A1 throws the ball to A2 who catches the ball while straddling the sideline. OOB on A2, B's ball where A2 was standing when he caught it.

3. Spot throwin, but otherwise like #2. Same result.

4. Spot throwin, A2 throws the ball to A2 who catches the ball, mostly in bounds, but with his foot on the OOB same endline as the throwin. Same result as #2 and #3.

5. spot throw-in. A1 throws to A2, who is standing completely out of bounds along the same line as A1. This is a violation on team A for having a 2nd player OOB on a spot throwin. However, I'm not sure where the ball gets put into play. I gotta find the rule book