Are there any differences between different methods in each of the following groups of element retrieve operations in
Returning null + removing operations:
Returning null + not removing operations:
Throwing exception + removing operations:
Throwing exception + not removing operations:
Similar duplications exists in insertion methods.
If there is no such difference, I would expect it to be mentioned in the javadoc of the methods (something like the good old "This is exactly like calling ..."). Is it only a sloppy documentation, or am I missing anything?