java object oriented programming interview questions

level of the base variablesub.methodofbase ();//Legal, sub inherits the method of base's protected typeSub.methodofsub ();//legal, which is the instance method of the sub itself }}The Java language does not support multiple inheritance, meaning that a class can only inherit another class directly. The reason here is that "one class directly inherits another class" is because the class can also have more than one indirect parent class, for example,

breakpoints when debugging1. The program executes one line at a2. Important variablesBasic Data type conversions:Double---> intint--->doubleConversions of reference data types:1. Upward transformationParent class Variable name = new Subclass instance ();A. The line code can perform successfully without castingB. Creating a parent class object is exactly a subclass instanceC. The method that is called when the method executes is the overridden method o

First, the last three test cases are submitted through theSecond, study the learning StringBuffer in the way of TDD, submit the unit test case and test passThird, using [WHITESTARUML] to model the code in the experiment two, the Hair class diagram (class diagram only two fewer classes)Iv. Unit test code and running success and code-on-Cloud codes linkTask: Develop a plural class Complex in TDD, which requires the following://define properties and generate Getter,setterdouble realpart;double imag

First, the purpose of the experiment1. Initial mastery of unit testing and TDD2. Understanding and mastering the object-oriented three elements: encapsulation, inheritance, polymorphism3. Initial mastery of UML modeling4. Familiarity with S.O.L.I.D principles5. Understanding Design PatternsIi. contents of the experiment(a) Unit testingPseudo-code: independent of the specific

and has produced languages such as FORTRAN, PASCAL, and C. Structured Methods extend the analysis and design of the program to the analysis and design of the project, and combine the technical support of the programming language to generate and develop the program. In 1980s, with the increasingly complex and huge application systems, structured development methods encountered some problems in engineering applications. During the same period, after 20

OO: Object-orientedOOP: Object-Oriented ProgrammingOOA: Object-oriented AnalysisOOD: Object-oriented designStructured programming: From top

) elements are properly nested8, valid XML in addition to satisfy the XML specification, but also to meet the corresponding DTD and schema definition of the element rules; Valid XML must be well-formed, but well-formed XML is not necessarily valid.9. DOM parsing: API based on tree structure; the entire XML document must be parsed and stored in memory; The client application can access the objects randomly; large documents can cause memory tension.10. Sax provides an event-driven model for parsin

class, and the variables that inherit from the parent class are hidden.Method Rewrite principle:1. Must have an inheritance relationship2. The overridden method cannot have more restrictive access rights than the overridden method, which can be the same.3. After rewriting the weight in the method can not be specific to the method to generate more exceptions (exceptions).4. Return value, method name, method must have the same number of arguments as the parent class. (That is, only modify the con

agile development and XP practice-4Refer to Http://www.cnblogs.com/rocedu/p/6683948.html to complete the learning of Java cryptography related content in pairs, combining refactoring, git, and code standards. Submit the learning Result Code cloud link and the representative result, must have the student number watermark.Run Experimental thoughts, through this experiment let me have a deeper understanding of

Recently Java opened an object-oriented curriculum, the teacher assigned the homework, ah, that is, what homework I don't how to describe, code as follows, do their own, code is very immature, please understand! That's about it:classstudent{PrivateString Stuno; PrivateString name; Private floatMath; Private float中文版; Private floatcomputer; /*Student () {}*/ P

Experimental content 1. Initial mastery of unit testing and TDD2. Understanding and mastering object-oriented three elements: encapsulation, inheritance, polymorphism3. Initial mastery of UML modeling 4. Familiarity with S.O.L.I.D principles 5. Understanding Design Patternsproblems encountered (tool find, installation, use, program editing, commissioning, running, etc.),Experimental building Web page can no

and set methods, you can invoke the properties and methods in the "partial" class. When new creates an object, it first allocates memory for object properties and initialization blocks, and performs default initialization. If there is a parent class, first allocate memory and perform initialization for the parent class object and initialization block. The initi

generally reflect the content of this chapter is more difficult to remember, the layout manager of the understanding of some difficulty. Hope that the teacher in the next experiment class in tandem with the study of this chapter framework, to help students understand the memory. This time the experimental work is relatively simple, the students can be completed on time, but several students did not write the summary of the experiment. Hope that students do not forget beginner's mind, with a pos

only one class.5, the variables defined in the interface are constants of public static final.6, the interface can inherit the interface, and can inherit multiple interfaces, a class implementation of an interface, not only to implement all the methods defined in the interface, but also the interface of the parent interface definition method is also implemented.7. Inheritance and Interfaces: Both the inheritance and the interface are abstract results; Inheritance is used to share c

parent class so the subclass must implement this method2. The parent class has an abstract method then the parent class must be an abstract class3. If subclasses do not choose to implement this method subclasses must be defined as abstract classesJudge:Abstract class must have abstract method (F) dispensableClasses with abstract methods must be abstract classes (T)Final1. Defines that the value of this property on the attribute is not allowed to change2. The definition on the class indicates th

convert the parent class to a subclass type by casting the type, and those members become visible, what happens when the conversion occurs?A class in the construction of the time, the first of its various levels of the parent class are constructed, the family is to Qi Qi whole. Write a test example here to see if you can get the parent reference.It appears that you cannot get a reference to the parent class instance.Classes that must be inherited: abstract classesClasses that cannot be inherite

floatMinfen = Fens[0]; intMinindex = 0; for(inti = 1; i ) { //Modify the minimum score if(Minfen Fens[i]) {Minfen=Fens[i]; Minindex=i; } } returnMinindex; } Public intGethightfenindex () {//Selection method: Think the first one is the lowest score floatMaxfen = Fens[0]; intMaxindex = 0; for(inti = 1; i ) { //Modify the minimum score if(Maxfen Fens[i]) {Maxfen=Fens[i]; Maxindex=i; } } returnMaxindex; }}In

Moonphases (read/write) Number of lines of code Post a blog volume/comment on the number of others ' blogs Time after school (hours) Learn the most rewarding program reading or programming tasks First week 20/10 1/0 5 Output 99 multiplication table using the Elipse development program Second week 60/20 1/0 6 Experiment Seven experiment Five Third week

No (5)NullPointerException NULL pointer exception (a method is called by an empty object)Abnormal:Try block: A block of code that may have an exception is not allowed to be missing and is not allowed to exist separately (can be combined with a catch finally block using the preceding 2 to show any accesses than either)Catch block: Handling exceptions thrown in a try blockFinally block: The code will execute anywayThrow: Using the throw new Exception ("

Joseph Ring Question:Package com.zb.test;public class Yuesefu{public static void Main (string[] args){500 people GroupBoolean[] B = new boolean[500];for (int i = 0;i {B[i] = true;//means that everyone is alive.}int sum = b.length;//Total is 500int index = subscript for number of 0;//int count = 0;//a variablewhile (Sum > 1)//When the number of surviving >1 people{if (B[index])//If this person is alive at the moment{count++;//to the number of reportsif (count = = 3)//If report 3 is shot{Total sum