//People類
package?com.immoc;
public?class?People?{
public?void?say()?{
?System.out.println("人類具有說(shuō)話的能力");
}
}
//Chinese類
package?com.immoc;
public?class?Chinese?extends?People?{
public?void?say()?{
?System.out.println("中國(guó)人說(shuō)中國(guó)話");
}
}
//American類
package?com.immoc;
public?class?American?extends?People?{
public?void?say()?{
?System.out.println("美國(guó)人說(shuō)英語(yǔ)");
}
}
//Test類
package?com.immoc;
public?class?Test?{
?public?static?void?main(String[]?args)?{
People?ch=new?Chinese();
People?am=new?American();
ch.say();
am.say();
?}
}
//APeople類
package?com.immoc;
public?abstract?class?APeople?{
public?abstract??void?say();
}

使用APeople類的時(shí)候把Chinese，American，Test類中的People改成APeople