Used to present one concrete case or illustration, often in explanations or when giving a representative sample.
I will explain by giving an example.
This is just one example of many problems.
To give one example of success, this company is famous.
As one example, I'll explain the changes of the four seasons in Japan.
This incident is an example of a social problem.
具体例 emphasizes a concrete, detailed example used to clarify an abstract point, while 一例 simply means 'one example' without that emphasis on concreteness.
Compound of 一 (one) and 例 (example). The reading is the standard on'yomi combination.