Type1 fonts have a fontmatrix to define the transformation matrix of the
glyphs for rendering.
This matrix is defined in the font file as :
/FontMatrix [0.001 0 0 0.001 0 0] readonly def

Usually this matrix is isotropic, meaning the scaling in the x direction is
the same as the scaling in the y direction.
However, in some cases, the matrix is anisotropic to synthesize a narrow
font.
Example for a HelveticaNarrow type 1 font :
/FontMatrix [0.00082 0 0 0.001 0 0] readonly def

Java seems to not take in account the scaling difference between the x and y
axis, and ignore the content of those values in the FontMatrix.