Re: help: Eclipse import cannot be resolved

In one project, we created a jar file(myJar.jar) containing
Person.class file.

Now, in Eclipse, I created a new project, hoping to use Person from
the Jar file: in "Properties", I have added myJar.jar in the
"Libraries". Now, I created this Java file(Student.java):

import department.resource.Person; //Eclipse shows in error red,
saying: "The import department.resource.Person cannot be resolved".

public class Student extends Person
{
...

}

I don't understand how come this be. F3 "Person" does bring me to
Person.class (no source attached). So Person.class is visible.

If I make Eclipse save Student.java, the import statement was deleted
automatically and Student.java has no red error anymore. However, when
I run Student.java as main application, Eclipse immediately throws
ClassNotFoundException for "Person".