Saturday, 17 December 2011

JSP Examples Tutorial - Runtime Polymorphism


<HTML>
    <HEAD>
        <TITLE>Runtime Polymorphism</TITLE>
    </HEAD>
    <BODY>
        <H1>Runtime Polymorphism</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from BaseClass...<BR>");
                }
            }
            class DerivedClass1 extends BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from DerivedClass1...<BR>");
                }
            }
            class DerivedClass2 extends BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from DerivedClass2...<BR>");
                }
            }
            class DerivedClass3 extends BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from DerivedClass3...<BR>");
                }
            }
        %>     
        <%
            localOut = out;     
 
            BaseClass a1 = new BaseClass(); 
            DerivedClass1 b1 = new DerivedClass1(); 
            DerivedClass2 c1 = new DerivedClass2(); 
            DerivedClass3 d1 = new DerivedClass3(); 
 
            BaseClass baseClassVariable;
 
            baseClassVariable = a1;
            baseClassVariable.print();
 
            baseClassVariable = b1;
            baseClassVariable.print();
 
            baseClassVariable = c1;
            baseClassVariable.print();
 
            baseClassVariable = d1;
            baseClassVariable.print();
        %>
    </BODY>
</HTML>

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