The method is supposed "set the rotational component (upper 3x3) of this matrix
to the matrix equivalent values of the axis-angle argument; the other elements
of this matrix are unchanged". But if initial matrix is zero, the modified
matrix is zero too. I suppose the scaling stuff that javadoc is talking about is
responsible for that ; but I think this method should set the rotational
component even when initial values are zeros.
Tested for Matrix4d and Matrix4f on 1.5.2 version and 1.6.0_2009-07-10 version.
Easy workaround is to set matrix to identity before setting the rotational