Files from software installed via snap are read-only. To configure Eclipse, however, we need to change its
eclipse.ini file. How to do it so, when pressing the Super key and clicking on Eclipse's logo, it uses the new configuration?
There are many possible solutions but the my favorite/simplest one is to use Menulibre:
/snap/eclipse/current/eclipse.inito somewhere you can edit it. Let us say, copy it to
Edit the arguments you want to update and save the file.
Search for "Eclipse."
Click in the Eclipse icon.
In the "Command" input, add the
--launcher.inioption after the binary path. In our example, we would replace
/snap/bin/eclipse --launcher.ini /etc/eclipse.ini %U
Click in Menulibre's "Save" button. I have only tested it on Unity and MATE, though, not sure it is going to work with GNOME 3.
So far, it is working to me.
 I, for example, changed
-Xms 256m -Xmx 1024m
-Xms 1024m -Xmx 4096m
 You may have to install it. A way to do it is to use APT:
$ sudo apt-get install menulibre