Basics of Abstract class

// abstract method can not have body
// abstarct method should be given body by the class which extends the abstract class
// abstarct class can not be instansiated and have at least on 1 abstract method or (class have abstract method must be declared abstract)
// use where some features are common like eat and sleep and some are not like makeNoise
// static abstract or constructor abstract must not be together
// reference can created ob abstract class


//interface I use interfaces when I see that something in my design will change frequently.

public abstract class animal
{
public void eat()
{
System.out.println ("eat\n");
makeNoise();
}

public void sleep()
{
System.out.println ("sleep\n");
}

public abstract void makeNoise();
//public abstract void makeNoise2();
}

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//When you declare a method as abstract, can other nonabstract methods access it? yes

public class cow extends animal
{
public void makeNoise() { System.out.println ("cow\n"); }
public static void main(String[] ar)
{
cow c = new cow();
//c.makeNoise();
c.eat();
}

}

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public class dog extends animal
{
public void makeNoise() { System.out.println ("dog\n"); }
public static void main(String[] ar)
{
dog d = new dog();
d.makeNoise();
}
}

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