How do I debug a chrome extension and its own host?

I have a Java program as my own messaging server and I have a Chrome extension.

The native application and extension communicate using the native message protocol . In a text message, the host application reads / writes standard input and output. The host application is launched by Chrome from the extension code.

I want to debug Java code. How can I connect to Eclipse after, for example, a message is sent to the Java program (which is my host) using an extension?