“Non-interactive” and “debugger” seem to be contradictory but bear with me. YouDebug is a tool which allows you to debug a running Java application with a script.
How could this be useful? From the website:
[…]your program fails at a customer’s site with an exception, but you can’t (or don’t want to) reproduce the problem on your computer[…]
Sounds like a familiar problem: Customer has a problem but they can’t give you access for security, legal or technical reasons. You can’t go there (too far away) of even if you could, security won’t let you touch anything.
In a nutshell, YouDebug is a debugger that is controlled by a Groovy script:
breakpoint("com.acme.SubStringTest",7) {
println "s="+s;
}
This sets a breakpoint in line 7 of “SubStringTest” and then prints the value of the local variable “s”.
Granted, it’s more time-consuming then doing it yourself (and you may need several attempts to get at the bottom of things) but you don’t have to install an IDE at your customer site, you don’t have to bring the source code along and technically, the customer is already running code that you wrote so from a legal and security point of view, this isn’t much different.
Dark Views 
It is very impressive, actually lead developer of YouDebug, is a famous man, also developer of the Jenkins. I hope it help me at customer side problems which can not reproduce at our environments. Thanks for sharing,