Add text and files to contact through the Zoho API?

Add text and files to contact through the Zoho API?

Hi!

I am new to Zoho and the Zoho API and have a few questions. Background:

I am going to write an application (preferably in Java) that will associate a received email (in GMail) to a Zoho contact with the the same email address as the sender address in the email.

To achieve this, I need to use the Zoho API to send a request that adds the given mail as a note or attachment to the contact list. To ensure that the contact exists, I will probably first have to search for the contact with a given email address.

After having carefully read the API specification site, I have the following questions:

Questions:
- Is the above possible (to add a contact note or attachment through the API)?
- In case an attachment is added, are the any file format restrictions? Is it possible to store the mail as html and the mail attachments in their original formats (pdf, docx, mpeg or whatever)?
- Is it possible to search for a contact with a specific email address?
- How is the authentication to the Zoho database handled? Is the ticket id enough, or is user and password required in the request?
- Where in my customers system do I find the target url (in your example, the target url is  https://crm.zoho.com/crm/private/xml/Contacts/getRecords)? When I run Zoho, the link on the address bar n  my browser does not seem to be that kind of link (sorry for the stupid question :).
- Didn't really get the the way to access the API. Is this done through web services, that is where can I find the actual API files? 

Thanks in advance!