Slurping a generic DER file?

[fjolsvit]

How would one read in and parse a DER encoded file of unknown content, and 
parse it to obtain the ASN1 structure? I've looked through the 
org.mozilla.jss.asn1 javaDocs and feel a bit overwhelmed by the number of 
classes available to me.  I suspect this problem has been solved 10^6 times 
in C.  What I'd like to have is a tool similar to the certificate 
informtion viewer in Mozilla.