Dear all, 

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()
    stack.push('a')
    stack.push('b')
    stack.push('c')
    assert stack.join('.') == 'a.b.c'


When using 2.5.1 it the assertion fails 


stack.join('.') == 'a.b.c'
|     |         |
|     c.b.a     false
[c, b, a]       2 differences (60% similarity)
                (c).b.(a)
                (a).b.(c)


It looks the semantic of `push` is changed. Is that expected? 


p