What are some similarities and differences between the movie Dead Poets Society and the novel Catcher in the Rye?

I find that the most significant similarity between both
works is their emphasis on authenticity of character.  Mr. Keating strives for his
students to "seize the day" and listen to their own voices in the construction of
reality.  Holden seeks to do much of the same and rails against the conformity in his
world.  The avoidance of "phonies" is a driving force in both works.  The cultural time
period of both works is also significant, as the decade of the 1950s is put "on trial"
in both.  I would also say that the indictment of the preparatory school culture is
something that both works feature in a fairly strong fashion.  At the same time, there
are significant points of divergence.  Salinger's work is much more bleak in its
forecast or hope for human redemption than Weir's film.  The depiction of adults in
Salinger's work is also much more dire and dour than the liberating figure of Mr.
Keating, who truly does care for the well- being of his students.  This is in stark
contrast to the adults at Pencey Prep, who are more concerned with increasing the
endowment of the school and making money or are thoroughly withdrawn from students. 
Finally, there is a stronger message of social solidarity in the film than in Salinger's
work.  The closing moments of each testify to this.  When the boys stand on their desk,
in opposition to the principal, and honor Mr. Keating with "O Captain, My Captain,"
there is a distinct and real feeling of social solidarity.  The last line of Holden's
narrative indicates that there is little hope for social connection and solidarity with
others.