I think I am mistaken. I cannot find sources that states the
Buddha ever said that Mahavira is enlightened. Well, 'mahavira'
literally means fully enlightened teacher. and the Buddha may
have just called him by his usual name.
The Buddha is known to have refuted a lot of Mahavira's teachings
on eternalism and karma and etc.
From the Buddhist perspective, Jainism commits the following
heresies;
1) Belief in a permanent soul (jiva) as opposed to the clear
Buddhist doctrine of anatma (no permanent soul).
2) The soul is considered eternal eternalism being against
the Buddhist teaching of the Middle Way.
3) A definition of karma that is purely materialistic in nature.
Buddhist karma is purely volitional or psychological in
essence.
4) For complete Jainist enlightenment, the physical body must die.
This is nihilistic in nature and opposed to the Buddhas teaching
of the Middle Way.
5) The Jainist practice of severe austerity is again, against the
Buddhas teaching of the Middle Way.
In short, there is nothing remotely similar between the jainist
teachings, and the teaching of the Buddha. Jainism may be
considered a more severe version of othodox Hindu teaching. Whereas
the Buddhas teachings are/were revolutionary in nature. No one in
His lifetime, taught the Dharma that he did. Mahavira the Jina
of Jainism, certainly did not. The Buddhas enlightenment was not a
mere intellection of the surveying of the contemporary
philosophical environment He found himself within. The Dharma is
not an idea, designed to be different from the other ideas
around at the time. The ego that leads to the need for
philosophical distinction, is the same ego that the Buddha
over-came through meditation, the essence of Zen practice.