Is this the good class design practice in Java?

public class OneClass {
        private AnotherClass anotherClass = new AnotherClass();

        private void doOneJob(){
            anotherClass.doOtherJob();
        }
    }

In the above code, AnotherClass is instantiated and held as a class variable of OneClass.

• What are the consequences of this design?
• Is it a good practice?
• Will this support unit testing?