Are the imports checked for validity at compile time? e.g. will the code containing an import such as java.lang.ABCD compile

Question :Are the imports checked for validity at compile time? e.g. will the code containing an import such as java.lang.ABCD compile?
Answer :Yes the imports are checked for the semantic validity at compile time. The code containing above line of import will not compile. It will throw an error saying,can not resolve symbol symbol : class ABCD location: package io import java.io.ABCD;