I've downloaded the Windows version of Java Commnunication API from java.sun.com. I extracted the zip file, placed the comm.jar at c:j2sdk1.4.0jrelibext folder.After that, i wrote a simple program to test whether i can get any serial/parallel port object from CommPortIdentifier.getPortIdentifiers();. It returns an empty enumeration, meaning that none of my ports are detected.
However I have checked that com1 port is exist using hyperterminal. I have RFID card reader and I am trying to read data from rfid card.
I've got a banner that displays on the web page and users can close it out by clicking an "X" button in its corner. Once it's closed, we track for that session that it remains closed, so a cookie gets set. I'd like subsequent requests to the server to be aware of this cookie so that the banner code is just not included in subsequent responses. (Sidebar: earlier I was just detecting the cookie after page load and then hiding the banner but it creates a lag where the banner is visible then suddenly pops away, making for poor user experience.)
I expect that even though Javascript set the cookie it would then show up in HttpServletRequest.getCookies() call, but there's actually a lot of cookies visible in Chrome Developer Tools on the client of my page that don't show up in .getCookies(). Does the HttpServletResponse.addCookie need called at some point first for the cookie to be passed back and forth to server?
What is the difference between JSESSION ID and Session?I red THIS blog, I got the explanation but I'm actually confused about JSESSION ID and Session.. In that blog, they told about JSESSION ID cookie. then What is the difference between JSESSION ID and Cookie?
i am trying to write a class method which will take in a string and returns a string which is the reversed version of that string. it compiles fine but when i try to run it it states Main method not found in class StringReverse,please define the main method as public static void main(String[]args). I am new to java and cannot figure out
import javax.swing.JOptionPane; public class StringReverse { public String reverseString(String str){ JOptionPane.showInputDialog(null,"Please enter word"); char c = str.charAt(str.length()-1); if(str.length() == 1) return Character.toString(c); return c + reverseString(str.substring(0,str.length()-1));}}
I've been beavering away with Java for a few months. But as with all languages the String implementation looks designed to trip up even experienced programmers.
My current development gets data from various sources outside my control. When I get a string I want to test if it is empty/null/or whatever. Simple enough one thinks.
But if you search the internet you see everone seems to have a slightly different approach. So what is the best way of determining that a string is not useful to you?
I've had success with this
if(string == null || string.length() == 0)
But I've seen people using methods - not necessarily of String (e.g equals, empty) and regular expressions.
What is the best approach to this considering coding efficiency and/or processing efficiency (accepting you'd have to be processing a lot of strings for the latter to be an issue).
I'm writing basically my first program for school. I've written small ones, following instructions, but this is the most vague. I'm having issues. I can't figure out what the error means. I'm not done with the code, but I think the ArrayList is throwing me off. I'm trying to gather user input and sum the total. Here's the code:
package graduationplanner; import java.util.ArrayList; import java.util.Scanner; import java.lang.Double; public class GraduationPlanner { public static void main(String[] args) {
I am having issues with the program below everything works but I can't figure out a way to add code that if a user just hits enter without inputting anything it says "entering in nothing is not a valid choice" I am stuck on how to compare a int to a string ...
//import statements import java.util.*; //for scanner class // class beginning public class Guess { public static void main(String[] args ) { //Declare variables area
I have the code below that just keeps getting the user's name and displaying it until the user enter's an empty string. Well, to simulate that, I just hit the keyboard instead of entering any name but for some reasons I am not seeing in my code, the programme just keeps looping.
System.out.println("Enter your name : "); Scanner st = new Scanner(System.in); while(st.hasNext()){ System.out.println("Enter your name : "); String name = st.nextLine(); System.out.println(name); if(name==" ") break; } System.out.println("you are out of the while loop now!!");
I made a guess a number program but I am having issue figuring out a way that when a user enter's in nothing for the program to spit out a message saying "hey entering nothing doesn't work try again" then ask for input. I have done some research and from what I have found is to read the input in as a String rather than int, and use something like Integer.valueOf() to get the integer value but I am completely lost on how to apply that to my program here is my code
//import statements import java.util.*; //for scanner class // class beginning public class Guess { public static void main(String[] args ) { //Declare variables area int guess, secretNumber = (int) (Math.random() * 10 + 1), lowGuess,highGuess;
I have an empty string and I want to add to it crosses and naughts. I want to simulate a board of TicTacToe game. My goal is print out 5 strings like this : "xox xxx oxo". There are 3 groups of symbols separated with a space. The crosses and naughts are filled randomly.
Random rand = new Random(); char[] characters = new char[] { 'x', 'o' }; int numOfTimes = 0; while (numOfTimes < 5) { String board = ""; String space = " "; for (int group = 0; group < 3 ; group++)
What is exact difference between them? Another thing is when I check (a==b) it retuns me false, but when I check a.equals(b) it returns me with true. Why So?
The following alert returns an added string instead of adding the var together to give me a total?
var tvHours = prompt('How many hours of Tv do you watch last week?'); var webHours = prompt('How many hours of internet surfing did you do last week?'); var gameHours = prompt('How many hours of video games did you play last week?'); alert(tvHours + webHours + gameHours);
Also can you store a var in an alert? e.g ( var time = alert(tvHours + webHours + gameHours); ???
The project is a program that allows the user to enter students and enter grades for each student. One of the requirements is that if there is already a grade stored for the student that it will display the previous grade. IF the user then enters a new grade the new grade will be stored. IF the user simply presses enter (enters an empty string) nothing is done. I have everything working except for the requirement of doing nothing if the user enters an empty string. If I just press enter at this point I get a NumberFormatException.
The below code is a method "setTestGrades" from the student class. This method iterates through each student object stored in an array list and then checks if there is a previous grade (Requirement# unset grades have to default to -1) before allowing the user to set a new grade.
public void setTestGrades(int testNumber) { //Sets the grade for the specified test number for each student in the arraylist. testNumber -= 1; Scanner input = new Scanner(System.in); for (int i = 0; i < studentList.size(); i++) { System.out.println("Please enter the grade for Test #" + (testNumber + 1) + " For Student " + studentList.get(i).getStudentName());
I must write a method that accepts a string and returns an int. The method should sum the unicode values of each character, so the string "ABC" should return 198. Also the only string class methods I'm aloud to use are length, charAt, and substring. I just don't know how the get the Unicode value.
I'm training myself with the EJB 3 technology. I would like to create a stateless bean that instead of returning a String, it returns an object. I tried in the same way I did with the first exercise, but I'm getting several errors.
I'm doing a problem where the area of a triangle is returned (if valid). However, I want to return a message (i.e. 'triangle is not valid) if the triangle is invalid.
I'm not sure how to go about to doing this as my method (called area) will only let me return doubles. Possible to return a string in an else within my area method?
public class MyTriangle { public static void main(String[] args) { //triangle is valid if the sum of any two sides is bigger than the third System.out.println(isValid(3, 4, 5)); System.out.println(area(543, 4, 5));
Actually I am working on java ee6 web application i tried to set value and max age for the cookie...but I was unable to set maxage what ever the max age value i give .it shows as -1.but my browser accepts and stores cookie.
I need to get the html in string when i hit the hit the jsp in servlets basically i need to put the output of jsp in pdf file when i hit one link i need to download that data in pdf file. I am using itextpdf.
//Get the output stream for writing PDF object OutputStream outStream=pResponse.getOutputStream(); ByteArrayOutputStream baosPDF = new ByteArrayOutputStream();
[Code] ....
I need to convert the sample download.jsp to html so that i can parse
Some methods such as ServletRequest's getParameterValues return a String array whereas others (e.g. HttpServletRequest's getHeaders) return an Enumeration. Do these return types need to be learned parrot-fashion, or is there some sort of logic to it?