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Technical General Java Sample Questions

1. Can a abstract method have the static qualifier?

   Answer: No

2. What are the different types of qualifier and What is the default qualifier?

   Answer: public, protected, private, package (default)

3. What is the super class of Hashtable?

   Answer: Dictionary

4. What is a lightweight component?

   Answer: Lightweight components are the one which doesn't go with the native call to obtain the graphical units.They share their parent component graphical units to render them.Example, Swing components

5. What is a heavyweight component?

   Answer: For every paint call, there will be a native call to get the graphical units.Example, AWT.

6. What is an applet?

   Answer: Applet is a program which can get downloaded into a client environment and start executing there.

7. What do you mean by a Classloader?

   Answer: Classloader is the one which loads the classes into the JVM.

8. What are the implicit packages that need not get imported into a class file?

   Answer: java.lang

9. What is the difference between lightweight and heavyweight component?

   Answer: Lightweight components reuses its parents graphical units.Heavyweight components go with the native graphical unit for every component.Lightweight components are faster than the heavyweight components.

10. What are the ways in which you can instantiate a thread?

    Answer: Using Thread class By implementing the Runnable interface and giving that handle to the Thread class.