I've found a evil change in the 2.5.1 when using an array list.
The following snippet is OK on 2.4.x
def stack = new ArrayList()
assert stack.join('.') == 'a.b.c'
When using 2.5.1 it the assertion fails
It looks the semantic of `push` is changed. Is that expected?
stack.join('.') == 'a.b.c'
[c, b, a] 2 differences (60% similarity)