What is shown in this picture?

Question

Iron

Dear, what is it? (in 1 column, 2 and 3) I would be very grateful if you provide links to sources where you can figure out what it is.

Answer 1

This is a hexdump image of some data (in your case, a class file, as Roman Mirr pointed out ) .
In the first column - the line offset from the beginning of the file.
The second column contains data in hexadecimal form, each two-digit number is 1 byte, 16 bytes per line.
In the third column, let's say "raw data" - the same data, in the form in which it was possible to print them. Non-printable characters are replaced with dots.

Answer 2

java class file