Identify five software engineering recommendation systems. Provide a concise description for

each system, focusing on the specific issue it addresses. Refer to the following source for

additional insights on recommendation systems in software engineering: M$.$ Robillard, R$.$ Walker,

and T$.$ Zimmermann, "Recommendation Systems for Software Engineering," IEEE Software, vol.

$27,$ no$.4,$ pp$.80-86,$ July$-$Aug. $2010,$ DOI: $10\mathrm{.}1109/$MS$\mathrm{.}2009\mathrm{.}161.$