This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
1) when you create a class and compile it and open and see the class using javap command .. that class file contains that it extends java.lang.object and a default constructor is created automatically..... But when you extends another class the java.lang.Object class is not appeared as extended why?
A Java class can only have one direct superclass. In your example, Temp extends Dummy. Dummy extends Object. This means Temp indirectly extends Object. But the "extends" keyword only means the direct superclass.
Note that in Java, it is convention to begin class names with uppercase. This will make your code easier for others to read because it will be what they are expecting.