First, Java foundation:
1, scope public, protected, private, as well as the difference
Publications in other packages can also be referenced. Protected is limited to classes in the same package, and private only can be used by yourself. When you don't write, you are like protected. 2, the difference between arraylist and vector
ArrayList needs pre-defined size, Vector is not used; Synchronized is synchronized, it is thread-safe, and ArrayList's method is not, because the synchronization of threads must affect performance, so ArrayList performance Good than vector. When the element in Vector or ArrayList exceeds its initial size, Vector doubles its capacity, and ArrayList only increases the size of 50%, so ArrayList is conducive to saving memory space. The same is the object collection, and the ArrayList can check by the compiler and the vector is not, so if you return to the object with a vector, the compiler is unable to check, and can only be found when running. 3. Different HashMaps of Hashmap and Hashtable HashMap and Hashtable Different have 16, havehtable is 11. Hashtable is an implementation of the Old Dictionary class, HashMap is an implementation of the MAP interface introduced by Java 1.2. Hashtable method is synchronized, while HashMap is not. 4, can CHAR type variables can not be defined as a Chinese? Why?
Can be defined. Because Chinese is also 16bit 5, there are several representations, what is it? Thread subclasses and Runnable interfaces achieve two 6. Synchronization There are several implementation methods, what is it? One is to synchronize the method: public synchronized MethodName (...) {....} The other is to synchronize the object (this object cannot be a null value): synchronized (Object) {.....}
7. Inheriting the order of execution of the class is generally a choice question, ask you what will print?
8. Internal category implementation?
Internal Class is a class in another class. From Java 1.1, you can declare another class in a class, which is very similar to the declaration fields and methods .9, garbage recycling mechanism, how to optimize the program?
The value is NULL when the variable is not used. 10, FLOAT FLOAT F = 3.4 is it correct?
Not. Types do not match. Change to float f = 3.4f. Second, JSP
1. What built-in objects have jsp? What is the role?
2, what actions are there? What is the role?
3, the difference between the two implementations of INCLUDE?
4, what is the difference between the two jump methods? What is the difference?
Third, servlet
1, talk about the life cycle of servlet?
2, the SERVLET version (forgot what two versions are asked)?
Fourth, JDBC, JDO
1, you may let you write a JDBC even Oracle program.
2, Class.Forname role? Why is it used?
3, what is JDO?
V. XML
1, what parsing technology is there? Is there anything?
2. What are your aspects of XML technology in the project? How to implement it?
3. How to solve Chinese problems when using JDOM to resolve the Chinese problem? How to resolve?
Six, EJB
1. What are the contents of EJB2.0? What are the differences in EJB2.0 and EJB1.1?
EJB2.0 defines three kinds of beans, Entity Bean, sessions, MVC aspects.
1, all parts of MVC have those technologies to achieve? How to implement?
Eight, design patterns:
1 All numbers ");} 10, CORBA
1. What is CORBA? What is the use?
