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41 to 45 Java Questions

41. What is nested class?
If all the methods of a inner class is static then it is a nested class.
42. What is HashMap and Map?
Map is Interface and Hashmap is class that implements that.
43. What are different types of access modifiers?
public: Any thing declared as public can be accessed from anywhere. private: Any thing declared as private can’t be seen outside of its class. protected: Any thing declared as protected can be accessed by classes in the same package and subclasses in the other packages. default modifier : Can be accessed only to classes in the same package.
44. What is the difference between Reader/Writer and InputStream/Output Stream?
The Reader/Writer class is character-oriented and the InputStream/OutputStream class is byte-oriented.
45. What is servlet?
Servlets are modules that extend request/response-oriented servers, such as java-enabled web servers. For example, a servlet might be responsible for taking data in an HTML order-entry form and applying the business logic used to update a company’s order database.

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16 to 20 Java questions

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Latest Java 11 to 15

11. What are the states associated in the thread? Thread contains ready, running, waiting and dead states. 12. What is synchronization? Synchronization is the mechanism that ensures that only one thread is accessed the resources at a time. 13. What is deadlock? When two threads are waiting each other and can’t precede the program is said to be deadlock. 14. What is an applet? Applet is a dynamic and interactive program that runs inside a web page displayed by a java capable browser 15. What is the lifecycle of an applet? init() method – Can be called when an applet is first loaded start() method – Can be called each time an applet is started. paint() method – Can be called when the applet is minimized or maximized. stop() method – Can be used when the browser moves off the applet’s page. destroy() method – Can be called when the browser is finished with the applet.

What is Servet ?

A servlet is a java class that extends an application hosted on a web server. Handles the HTTP request-response process (for our purposes) Often thought of as an applet that runs on a server. Provides a component base architecture for web development, using the Java Platform The foundation for Java Server Pages (JSP). Alternative to CGI scripting and platform specific server side applications.