Problem not being able to download artifacts when installing plugins in Eclipse

Question

We have been developing a plugin, and it has been installed successfully so far.

However, for Eclipse 2023-12 and Eclipse 2024-03 versions

If you do not check the Contact all update sites during install to find required software option during installation, the following message will be displayed and installation will not be possible

An error occurred while collecting items to be installed
     session context was:(profile=epp.package.jee, 
     phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
     Can't download artifact
     osgi.bundle,com.google.guava,15.0.0.v201403281430 required by com.google.guava[15.0.0.v201403281430], 
...

If you use the Contact all update sites during install to find required software option, I know that if I can't find the plugin I need, I'll look for a replacement.

Of course, this method solves the problem, but it involves installing a replacement plugin, which is not what I wanted.

I expected that Eclipse's policy had changed based on the fact that it does not work with certain versions.

Also, I confirmed that the signature information of the plugin I created and the signature information of com.google.guava,15.0.0.v201403281430.jar where the problem occurs are different.

I thought that the plugin I was trying to install had different signature information, so downloading from the p2 directory was blocked.

In order for the plugin I created to operate properly, com.google.guava,15.0.0.v201403281430.jar is required. Accordingly, I removed the existing signature of the com.google.guava,15.0.0.v201403281430.jar plugin and applied the same signature method used to sign the plugin I created, and the problem was resolved.

It has been solved, but since it is based on guesswork, I would like to hear from someone who experienced the same problem as me and share their experience.

1. If the signature information of the plugin I am trying to install is different as I expected, will the p2 directory block the download? (This is not a problem with the Internet, firewall, or update site access.)

2. If number 1 is correct, which version of Eclipse was it?

3. Even though it is not a plugin we created, will there be any licensing issues if we remove the expired signature and sign it ourselves and distribute it?

You may be asked to update the guava version or upgrade the Eclipse version. However, the plugin I created is a company resource, and I cannot arbitrarily upgrade the target platform version. This is because the goal is to support as many versions of Eclipse as possible.