We have seen how to write a custom field in one of the previous tutorials. Writing the field is one thing but making it available to one of the JIRA's most powerful functionality, i.e. Search, is another!
So how do we do that? In most cases, you wouldn't need a custom searcher. Instead you can use the built in custom field searchers in JIRA itself. The list includes, but not restricted to, Text Field Searcher, Date Searcher, Number Searcher, User Searcher etc.
Creating an Issue in JIRA from other applications, like custom built UI for instance, is a common behaviour. It is pretty easy because JIRA provides us with the SOAP or XML/RPC interfaces. SOAP is recommended as it supports more operations which you might be using along with the Create!
Creating a JIRA SOAP client is pretty easy and is detailed in my previous tutorial. I am going to assume that you have the client created and a sample test done to ensure you are connected to your JIRA.