how does intellij calculate the 4 digit ids of object instances? [duplicate]

Question

When using Intellij's debugger, the variables in scope are displayed using a 4 digit identifier, marked in red in the following screenshot.

This identifier seems to be calculated based on the object's identity.

What exact code is used to get the 4 digit number for a given object instance?

Answer 1

I don't think you should rely on that id being calculated in any special way. It's internal to IDEA (or JVM) and I don't think it holds any relevance except to track objects during execution.

However, I find it useful to name objects during debug. I believe the shortcut is F11 (click once on the object in debug window first) and just give it a name that is meaningful for you during debugging. That object will always hold that name during the current session of debugging.