Eclipse – Yellow highlight and substitution of words with autocomplete

Solution for Eclipse – Yellow highlight and substitution of words with autocomplete
is Given Below:

I have a problem with Eclipse in Debian Buster.

Every time I activate autocomplete near a word, the same is highlighted in yellow and, if I confirm completion, it is replaced.

eclipse autocomplete and highlight problem

In Windows I didn’t have this problem; I believe it is some Eclipse setting but I don’t know how to disable it.

Thanks in advance.

In Eclipse 2020-12 (4.18) the default behavior for the Java content assist changed from Completion Inserts to Completion Overwrites, which can be configured in Window > Preferences: Java > Editor > Content Assist at the top.

See also my video showing this new default behavior of the content assist and how the old behavior can be restored.