Exception handling in Ruby

Like Java, Ruby has the exception handling capabilities.
Handling the any type of exceptions in ruby is pretty simple,
Just use begin rescue pair w/t specifying what kind of exceptions you do want to catch.

begin
code
code
resuce Exception => msg
puts "Something went wrong ("+msg+")"
end

rescue/raise is used to signal error conditions. This is analogous to
Exceptions in Java or C++.

Throw/catch is used to unwind the stack to a desired point. It's like
a labeled break. For example:

catch(:done){
loop {
do_work
if time_to_stop? throw :done
}
}

It's nice because you can break out of arbitrarily nested loops/blocks/etc.

There appear to be 2 separate exception mechanisms in Ruby, catch/throw and
rescue/raise/retry. Is this right?

Not really. A throw just lets one unwind from some deep nesting without
generating a back trace, passing some value along to the catch.

It is much faster and lighter weight than the exception mechanism, and should
be used for cases where a fast, lightweight escape from some deep place is
wanted, perhaps with some passing of data from the deep place to the shallow
place, but where an actual exception isn't needed.