4 Inheritance is the process of deriving a new class from an existing class.
4 Inheritance can be formed mainly in five ways:
§ Single inheritance
§ Multilevel inheritance
§ Multiple inheritance
§ Hierarchical inheritance
§ Hybrid Inheritance
Single inheritance:
If a class is derived from another class, it can be called as single inheritance.
Syntax:
class A
{
…
}
class B extends A
{
…
}
Example:
class alpha
{
public void show1()
{
System.out.println(“hello alpha”);
}
}
class beta extends alpha
{
public void show2()
{
System.out.println(“hello beta”);
}
}
class Test
{
public static void main(String as[])
{
beta b1=new beta();
b1.show1(); // prints “hello alpha”
b1.show2(); // prints “hello beta”
}
}
Multilevel inheritance:
If a class is derived from the class, which is derived from another class, it can be called as multilevel inheritance.
Syntax:
class A
{
…
}
class B extends A
{
…
}
class C extends B
{
…
}
Example:
class alpha
{
public void show1()
{
System.out.println(“hello alpha”);
}
}
class beta extends alpha
{
public void show2()
{
System.out.println(“hello beta”);
}
}
class gamma extends beta
{
public void show3()
{
System.out.println(“hello gamma”);
}
}
class Test
{
public static void main(String as[])
{
gamma g1=new gamma();
g1.show1(); // prints “hello alpha”
g1.show2(); // prints “hello beta”
g1.show3(); // prints “hello gamma”
}
}
Multiple inheritance:
If a class is derived from two or more classes, it can be called as multiple inheritance. Java does not support this type of inheritance.
| Hierarchical inheritance |
| Derived class 2 |
Syntax:
class A
{
…
}
class B extends A
{
…
}
class C extends A
{
…
}
Example:
class alpha
{
public void show1()
{
System.out.println(“hello alpha”);
}
}
class beta extends alpha
{
public void show2()
{
System.out.println(“hello beta”);
}
}
class gamma extends beta
{
public void show3()
{
System.out.println(“hello gamma”);
}
}
class Test
{
public static void main(String as[])
{
beta b1 = new beta();
b1.show1(); // prints “hello alpha”
b1.show2(); // prints “hello beta”
gamma g1= new gamma();
g1.show1(); // prints “hello alpha”
g1.show3(); // prints “hello gamma”
}
}
Hybrid inheritance:
This could be the combination of multiple and multilevel inheritance. Java does not support this type of inheritance.
| Base class 1 |
| Multiple inheritance |
| Base class 2 |
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