the import java.io cannot be resolved code example

Example 1: restcontroller cannot be resolved to a type eclipse

<dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>4.1.6.RELEASE</version>
    </dependency>

Example 2: the import junit cannot be resolved maven

Properties -> Java Build Path -> Libraries -> Add Library -> JUnit -> Junit5