java programming quiz questions and answers

++;Parent.printvalue ();　　((child) parent). myvalue++;Parent.printvalue ();}}Operation Result:Summarize:When a subclass has the same method as the parent class, and a parent class variable refers to a subclass object, which method is called, determined by the object's own "true" type, that is, the object is a subtype, it calls the method of the subtype, it is the parent type, and it invokes the method of the parent type. This feature is actually a concrete representation of the object-oriented "

digits to accurately represent (even need infinity), and the double type of the value of only 64bit, the back of the number of bits will definitely bring error, can not get "mathematically accurate" results.2. Questions about the number of bits and ranges represented by each data type in JavaA : The conversion of data types in Java, from high-precision like low-precision conversion will have a loss of p

= In.readline ();//read a line of content while(Line! =NULL ) { if(Character.isletter (line)) I++; Else if(Character.isdigit (line)) J++; ElseF++; Line=In.readline (); K++} in.close (); System.out.println ("Letter" +i+ "number" +j+ "Space" +j+ "number of lines" +k)}Catch(IOException iox) {System.out.println ("Problem reading" +fileName); } }}4, if there is a string "6sabcsfs33", with the most rapid way to remove the character "ab3", can not use the

single-threaded program can not produce OutOfMemoryError exception, using multithreading will also appear outofmemeoryerror, because the stack is thread-private, line multithreading also overflow method area3, JVM stack space allocation over the General Assembly caused by what problemshttp://blog.csdn.net/qq_30739519/article/details/510425844. How to detect dead loops and deadlocks in the JVMDeadlock: http://www.cnblogs.com/ilahsa/archive/2013/06/03/3115410.htmlDead Loop: http://blog.csdn.net/s

Question OneWrite a method that uses the above algorithm to generate a random integer of a specified number (for example, three). Answer: xn+1= (7^5*XN) mod (2^31-1)Program source code :import java.util.Random;import Java.util.Scanner; Publicclass Randomcount{ PublicStatic void Main (string[] args){Random rand=new random ();System. out. Print (" Please enter the number of random numbers you want to output:");Scanner in =new Scanner (System. in);int n,x;N=in.nextint ();X=rand.nextint (100); for

Jame Dean 2016-12-06 17:12 Basic Knowledge section (90 points) one, the single choice question (altogether 12 questions, each question 3 points, altogether 36 points. ) 1, Java is from (B) language improvement redesign. A) Ada B) C + + C) pasacal D) BASIC 2. Which of the following statements is correct (B) A Java program generates machine code after compiling B

Java Basics 1. What are the features of object orientation? 1. Abstraction: Abstraction is to ignore those aspects irrelevant to the current target in a topic, so that you can pay more attention to the aspects related to the current target. Abstraction is not intended to understand all the problems, but to select a part of the problem. Abstract: Process abstraction and data abstraction. 2. Inheritance: Inheritance is a hierarchical model that connects

inheritance of the thread class and implementation of the Runnable interfaceThere are two kinds of implementations of synchronization, namely Synchronized,wait and notify 　　What is the difference between dynamic include and static include in 11.JSP? Dynamic include using Jsp:include action to implement It always checks for changes in the contained files, suitable for inclusion of dynamic pages, and can be used with parameter Static include with the include pseudo code implementation, will not

output is j=1] A, program compilation error B, J=1 C, j=2 D, j=0 4. In Java, the following description of the constructor is correct (). (Select an item) [Answer: D] A, the class must have an explicit constructor (the system defaults to add a constructor to a class that does not have a constructor defined, and is hidden) B, its return type is void (although the constructor does not return any value, but does not mean that it is a void type) C, it and

between dynamic include and static include in 11.JSP? Dynamic include using Jsp:include action to implementIt always checks for changes in the contained files, suitable for inclusion of dynamic pages, and can be used with parameterStatic include with the include pseudo code implementation, will not check the file contains changes, applicable to include static pagesSecond, Java programming and program runni

1 . What are worker threads and SwingWorker and how do I use them? When a swing program needs to perform a long task, it is usually done using a worker thread. Each task executes in a worker thread, which is an instance of the Javax.swing.SwingWorker class. The SwingWorker class is an abstract class; You must define its subclasses to create a SwingWorker object, which is usually done using anonymous inner classes. SwingWorker provides some features of communication and control: [1]swingworker su

Java basics-six typical xml q A-general Linux technology-Linux programming and kernel information. For details, refer to the following section. I. HTML is so popular. Why should we develop XML? Simply put, HTML cannot be completed, and we want the task to be completed in XML. The reason is very simple. The task to be completed in XML must be completed by the meta-tagline, while HTML is just an example of

C ++ programming ideology (second edition) Chapter 2nd object creation and use (exercises and answers), java programming ideology (second edition) Exercise-related code Hello. cpp Stream2.cpp Nomconv.cpp Fillvector.cpp 2-1 modify Hello. cpp so that he can print your name and age (or your shoes, dog's age, etc., as l

50 typical Java programming questions, 50 java programming questions There are n integers, so that the previous numbers are shifted to the next m positions, and the last m number is changed to the first m number. Public class Exam

table is not used at all. Compile with Javac, and then run it in Java. If you're using a different development environment than the JDK, learn how to compile and run it in your environment Public class javathinking { publicstaticvoid main (string[] args) { System.out.println ("Hello,world");} }Exercise 3: Find the code snippet that contains the atypename, rewrite it as a complete program, and then compile, runclass atypename{ pub

integers x, y, Z, please put these three numbers from small to large output. Program Analysis: We try to put the smallest number on the X, first compare x with Y, if x>y the value of x and Y, and then compare X with Z, if x>z the value of X and Z, this will make x the smallest. * @author Tong * */public class Sortthreenum {public static void main (string[] args) {Scanner Scanner = new Scanner (System . in); System.out.println ("Please enter the first integer:"); int x = Scanner.nextint (); Syst

word key that needs to be counted, then take advantage of Java's own indexof () Find the first occurrence of the word position,//statistics plus 1, and the previous statistics of the string truncated, in the remaining fields to match. int times = 0;while (true) {int index = Str.indexof (key), if (Index! =-1) {times++;str = str.substring (index + key.length ( ));} Else{return Times;}}}Operation Result:Source Code 3:Package Com.yue.day11;import Java.util.scanner;public class Yanghuitri {/** * Pri

); System.out.println ("Please enter the lower limit of the number:"); int low = Scanner.nextint (); System.out.println ("Please enter a number cap:"); int high = Scanner.nextint (); if (Low>high) {System.out.println ("you entered the wrong data, please re-enter!") "); System.out.println ("Please enter the lower limit of the number:"); low = Scanner.nextint (); System.out.println ("Please enter a number cap:"); high = Scanner.nextint ();} SYSTEM.OUT.PRINTLN (all primes between low+ "-" +high+ ")

) {Integer a = Integer.parseint (num);Long sum = 0;Long subsum = 0;for (int i=1;iSubsum = Subsum*10+a;sum = sum+subsum;}return sum;}}Operation Result:3. Procedure 3Package Tong.yue.hong;Import Java.util.Scanner;/** Title: If a number is exactly equal to the sum of its factors, this number is called the "end number", that is, the non-repetition factor other than itself and equal to itself. Programming to find all the finished numbers within M.* For exa

java.util.scanner;/* * Title: Decomposition of a positive integer factorization. For example: Enter 90 and print out 90=2*3*3*5. Program Analysis: The decomposition of n factorization, should first find a minimum prime number k, and then the following steps to complete: (1) If the prime number is exactly equal to N, then the decomposition of the factorization process has ended, printing can be. (2) if nOperation Result:2. Procedure 2Package Tong.yue.hong;import java.util.scanner;/** * Title: Us