Which is a valid abstract class?
A.
public abstract class Car { protected void accelerate(); }
B.
public interface Car { protected abstract void accelerate(); }
C.
public abstract class Car { protected final void accelerate(); }
D.
public abstract class Car { protected abstract void accelerate(); }
E.
public abstract class Car { protected abstract void accelerate() { //more car can do }}
D
Answer: D
Explanation:
A valid abstract class needs to have an abstract modifier defined before the class modifier and it needs at least one abstract method without a body.
an abstract class may or may not have an abstract method