Basic j2EE concepts

Java basics:
1. Scope: public, protected, private, and no-write differences
2. What is the difference between ArrayList and Vector? What is the difference between HashMap and Hashtable?
3. Can a char variable be defined as a Chinese character? Why?
4. What are multiple representation methods of multithreading? What are the implementation methods of synchronization?
5. The sequence of class execution during inheritance is generally multiple-choice questions. What will you print out?
6. How do I implement internal classes?
7. How to optimize the garbage collection mechanism?
8. Is float f = 3.4 correct?
Jsp
1. What built-in objects does jsp have? What are their roles?
2. What actions does jsp have? What are their roles?
3. What are the differences between the two include methods?
4. What are the two jump methods? What is the difference?
Servlet
1. What is the Servlet lifecycle?
2. What are the differences between Servlet versions?
Jdbc and Jdo
1. You may be asked to write a program that connects Jdbc to Oracle.
2. What is the role of Class. forName? Why?
3. What is Jdo?
Xml
1. What Parsing Technologies does xml have? What is the difference?
2. What aspects of xml technology have you used in your project? How to implement it?
3. How can I solve the Chinese problem when parsing xml files using jdom? How to resolve it?
EJB
1. What does EJB2.0 have? Where are they used? What is the difference between EJB2.0 and EJB1.1?
MVC
1. What technologies are used to implement MVC? How to implement it?
Design Patterns:
1. What design patterns are used in development? In what scenarios?
JavaScript
1. How to verify the number type?
CORBA
1. What is CORBA? What is the purpose?
Who will answer this question!
-------------------------------------------------------------
Answer part.
1. Scope: public, protected, private, and no-write differences
Public classes in other packages can also be referenced. protected is limited to classes in the same package, and private is only available to you. It is the same as protected when not writing.
2. What is the difference between ArrayList and Vector? What is the difference between HashMap and Hashtable?
The ArrayList must be pre-defined, and the Vector does not. The default initialization capacity (default initial capacity) of HashMap and Hashtable is 16, and Hashtable is 11.
3. Can a char variable be defined as a Chinese character? Why?
Yes. Because Chinese characters are also 16bit.
4. What are multiple representation methods of multithreading? What are the implementation methods of synchronization?
View the jdk Documentation.
5. The sequence of class execution during inheritance is generally multiple-choice questions. What will you print out?
For more information, see.
6. How do I implement internal classes?