protected void randomise() {
int[] copy = new int[];
// used to indicate if elements have been used
boolean[] used = new boolean[array().length];
Arrays.fill(used,false);
for (int index = 0; index < array().length {
[Code] .....
I am working on an Eclipse based project that uses WTP Eclipse plugin. Since I have switched security on in that plugin (by checking "Enable Security" check box on) I'm having multiple problems. I get a stack of security errors - attached in this post. I also show my java.policy file. Because the of the mass exceptions I list only the top, although I have attached a docx file with full thing.
Here is my java.policy file:
grant codeBase "file:${catalina.base}/wtpwebapps/App/WEB-INF/lib/hibernate-core-4.3.5.Final.jar" {
permission java.util.PropertyPermission "*", "read, write";
};
grant codeBase "file:${catalina.home}/lib/catalina.jar" {
permission java.lang.RuntimePermission "*";
[Code] ....
Exceptions:
15/08/2014 10:12:43 PM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path:
C:Javajdk1.6.0_33in;C:WINDOWSSunJavain;
C:WINDOWSsystem32;C:WINDOWS;
[Code] .....
I am taking the Class Algorithms and Datastructures and got an assignment for Lab that really throws me off. The goal is to create an Array out of a given CSV file, implement several Methods that get the size of array, etc.
I am still stuck in the first part where the CSV has to be imported into the Array. My problem is that I need a mechanism that figures out the needed size for the Array, creates the array, and only then transfers the data from the CSV.
The list consists of the following wifi related values:
MAC-Adress, SSID, Timestamp, Signalstrength.
These are on the list, separated by comma. The Columns are each of these, and the rows are the four types of values making up the information on a certain wifi network.
The catch is, we are not allowed to use any of the following:
java.util.ArrayList
java.util.Arrays
and any class out of java.util.Collection.
So far I used the BufferedReader to read in the file and tried to implement the array, but I get an arrayindexoutofboundsexception.
Below is my Code (Its still an active construction zone):
public class WhatsThere {
public WhatsThere(String wifiscan) throws IOException {
}
public static void main(String[] args) throws IOException {
// WhatsThere Liste = new WhatsThere(String wifiscan);
String[][] arrayListe = new String[0][0];
[Code] ....
A java program to print 10 random numbers between 512 and 1024 and then finds the smallest and biggest numbers from the list using only one loop
class BSLab4d {
public static void main (String[] args){
int[] nums = new int[10];
int largest = nums[0];
int x = 0;
int smallest = nums[0];
int y = 0;
[code]....
I have the textfile which has lines:
A B 2 midterm 100
C D 1 final 90
C D 1 midterm 90
A B 2 final 80
**NO ARRAYLIST IS ALLOWED!** And the textfile is passed into the method. How to get the size for the array non-randomly inside the method from the passed Scanner file?? What if you have lots of numbers of lines, so how could that be done?
I have doubts about this line Exam[] object = new Exam[12];
Java Code:
public static Exam[] readAllExams(Scanner s) throws ArrayIndexOutOfBoundsException
{
String firstName = "";
String lastName = "";
[Code].....
I am using what is known as a Depth First Search to solve a maze using my own Stack created class for an assignment. The reason I believe I am getting this error is because my program is never meeting the `finishSpot` condition. I have used the debugger and it looks like it is infinitely stuck at the Point before the `finishSpot`. My logic seems to be mostly correct except until the point where my maze solver tries to finish the maze.
This is a sample maze:
*****
*s* *
* * *
* f*
*****
Here is my Main which uses my created Stack class.
//Creates a Stack and determines the start and endpoints.
public static void solveDFS( char [][] maze ){
LinkedStack stack = new LinkedStack();
Point currentSpot = findPoint( maze,'s' );
Point finishSpot = findPoint( maze, 'f' );
findPath( maze,currentSpot, finishSpot,stack );
[code]....
The array size is fixed improve it to automatically increase the array size by creating a new larger array and copying the contents of the current array into it .I am using a course class and here is the code for the class
public class Course {
private String courseName;
private int numberOfStudents;
private String[] students = new String[100];
public Course(String courseName)
[Code] ....
As you can see I have the array set to size 100, how do i make so it increments each time the user adds a student.
I come to the point: I just started to learn java through various manuals and in one of them I came across a declaration of an array that I do not understand:
int[][] multiArr = new int[2][];
the manual says that you can allocate the multidimensional array multiArr by defining size in only the first square bracket but I can't undestand how you can use this array. Seems to be no way to store data with it!
I'm working on an assignment that says the following.
" The array size is fixed in Listing 10.6. Improve it to automatically increase the array size by creating a new larger array and copying the contents of the current array to it.Implement the dropStudent method.Add a new method named clear() that removes all students from the course.
Write a test program that creates a course, adds three students, removes one, and displays the students in the course."
10.6 Listing
public class Course {
private String courseName;
private String[] students = new String[100];
private int numberOfStudents;
}
public Course(String courseName) {
this.courseName= courseName;
[Code]...
My Test Code based off of book
public static void main(String[] args) {
Course course1= new Course("Business");
course1.addStudent("Jay");
course1.addStudent("Silent Bob");
course1.addStudent("Dante");
course1.dropStudent("Jay");
[Code]....
My adjusted 10.6
public class Course {
private String courseName;
private String[] students = new String[100];
private int numberOfStudents;
}
public Course(String courseName) {
this.courseName= courseName;
[Code]...
The problem I'm having is, for the first part of the question where I need to automatically increase the array size. I'm really not great at this stuff. I have tried breaking it down, but can't "get it", I guess.
I assume, it'd be a loop that checks to see if the student array is full and if so, do the increaseArray() part, by maybe multiplying the student array and then assigning it. I just don't know how to do it haha.
My *best* attempt at the loop so far has been
if (students == students.length){
int bigArray = 2*students.length;
String increaseArray()= new String[students];
System.arraycopy(students, 0, increaseArray, 0, students.length);
students= increaseArray;
but,yeah... Doesn't seem to be right.
I am having trouble with an assignment. I need the user to input the size of the array and print when asked. In my program, it prints 100 numbers instead of the user input number, such as 15.
import java.util.Arrays;
import java.util.Scanner;
import java.util.Random;
public class Lab9 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int [] values = new int [100];
[Code] .....
I am trying to make a code that copies the users String to a char array. However, I am in a predicament: since I would not know the exact size of the users String I am left with the options of either making my array large by default, filled in with, lets say 25, empty spaces per index OR starting out with a default size of 1, with an empty space, and then some how increase the size from there.
At this moment I am leaning on the first option, creating a large default array and then deleting the unused values. However, this brings me to my actual question: if I set the non used indexes to null, if that wont give me an error, would that change the size of my array?
Ex:
//lets say i finally copied all of the values and this is the result
char[] word = {'b', 'o', 'b', ' ', ' '};
for(int i = word.length(); i > 0; i--){
if(word[i] == ' ')//delete the value so the size decreases
word[i] = null;//if possible
}
Implementation of the nested for loop. I thought it was going to go smoothly but apparently not.Purpose: This program is meant to print out all the prime numbers up to a certain range using the algorithm Sieve of Eratosthenes.
Update output: Works as expected.
Java Code:
import java.util.Scanner;
import java.util.ArrayList;
public class PrimeFactors
{
static ArrayList<Double> primeList = new ArrayList<>();
static double range = 0;
static double maxPrime = 0;
static double primeTester = 0;
[code]....
Is this possible in Java?
public void doSomething(int[4] year){
}
What I am trying to do is to get the person who is using the method to send a year in the format 1998 and so on.
What would be the best way to accomplish this?
I'm just putting together a little 'horse racing' program while I'm learning Java, and I have a class called Race that creates an array list of thorougbred horses called field, and asks the user to enter then names of the each horse in the field, with a maximum of 14 horses. The problem occurs with the current code that I have:
import java.util.*;
public class Race {
RaceHelper helper = new RaceHelper();
ArrayList<thoroughbred> field = new ArrayList<thoroughbred>();
public void setField() { //enter the horses in the race and determine the size of the field
[code]....
the statement of the index position and current size was for me, so I could see what was going on.What I don't understand is the while loop. not that the class doesn't compile and run (you can see that it does), it's the output. Why does the <= sign allow one more entry and increase the size of the field to 15?
Less than or equal to 14 should give a maximum field size of 14, right, With the starting object at index position at zero and going up to 13, for a total size of 14 thoroughbred objects if I just use while (field.size()<14) or a for loop, then the output is fine; it allows a max of 14 entries and prints the results. I thought it had something to do with the size being zero based, but that doesn't seem to matter -- unless it does matter and I'm missing it. why the comparison I'm using produces this output? a field of 14 horses shouldn't matter whether it's zero or 1 based, as long as the size of the field is 14, so why the extra entry with this while condition?
I'm working on a program to create a blackjack game using objects (one for card, deck. and hand). Withing my hand object I am trying to add cards to the hand but it is only adding the last card i try to add and giving null values for the the ones before.
class BlackJackHand {
private BlackJackCard [] hand;
public void addToHand(BlackJackCard c) {
if (hand == null) {
BlackJackCard [] tempHand = new BlackJackCard[1];
tempHand[0] = c;
hand = tempHand;
[Code] ....
What I want this section to do is add cards to the current hand. I was intending for it the hand to be null at first and the if(hand == null) piece to add the card the first time and then the else piece would be used when the hand already has at leas one card. I want the else section to create a temporary array that is one larger than my current hand, copy the cards from the old hand to the new hand, and then add a new card to the last space before rewriting the old hand as what the temporary hand is.
The code I am using to test if the addToHand() is working is
class BlackJackTest
{
public static void main (String[]args) {
BlackJackCard c1= new BlackJackCard(1,0);
BlackJackCard c2= new BlackJackCard(1,4);
BlackJackCard c3= new BlackJackCard(1,5);
BlackJackHand h1 = new BlackJackHand();
[Code] .....
BlackJackCard has the parameters (int suit, int value)
This should print:
ace of clubs
4 of clubs
5 of clubs
but instead prints:
null
null
5 of clubs
Write a program to create an integer array of size 20. Then, the program should generate and insert random integers between 1 and 5, inclusive into the array. Next, the program should print the array as output.
A tremor is defined as a point of movement to and fro. To simulate it, the program will generate a random number between 0 and 19, which represents the location in the array (i.e. index number). Then, the 3 numbers to the left and right of this location should be reset to the value 0. If there isn't 3 numbers to the left and right you may assume a lesser number depending on the boundaries of the array.
Then, the final array should be printed as output. There is no user input for this program.Your program must include, at least, the following methods:
-insertNumbers, which will take as input one integer array and store the random numbers in it.
-createTremor, which will generate the random number as the location and return it.
A sample run of the program is shown below:
Sample output #1:
Array:1 2 2 3 1 5 4 2 3 4 4 2 1 1 3 2 1 4 3 2 1
Random position: 5
Final Array:1 2 0 0 0 5 0 0 0 4 4 2 1 1 3 2 1 4 3 2 1
Write a program to initialize and display variable size array.
View Replies View RelatedI'm making a program that selects classes from a database via a jcombo box and then populates a time table with the class times.
I've used a custom cellrenderer that extends DefaultTableCellRenderer to text wrap the information and change the background of the cells.
It works but when i minimize the program it goes all black and if I double click I get a new JTextArea opening up on the timetable and when I minimize the program and go to open it again i get an "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException" and the cell render seems to be called again even though i haven't rerun the program.
This is the cell renderer that I built
public class TimesTableCellRenderer extends DefaultTableCellRenderer {
private int minHeight = -1;
private final JLabel label = new JLabel();
private final JTextArea textArea = new JTextArea();
public TimesTableCellRenderer(){
super();
textArea.setLineWrap(true);
[Code] ....
I am trying to print a loop inside an array of a greater size than the loop itself. Like for example I have an array of size 7 but it has only 3 elements.
int[] array=new int[7]
array[0]=2;
array[1]=3;
array[2]=4;
now what I want to do is print these three numbers in a loop so that my array[3]=2;array[4]=3;array[5]=4 ...... till the last one. Also the array could be any size and not just 7.
I am trying to create an array list without using the built in arrayList class that java has. I need to start the array being empty with a length of 5. I then add objects to the array. I want to check if the array is full and if not add a value to the next empty space. Once the array is full I then need to create a second array that starts empty and with the length of the first array + 1.
The contents of the first array are then copied into the new array without using the built in copy classes java has and then the new array ends up containing 5 elements and one null space the first time round. The first array is then overwritten with the new array containing the 5 elements and the null space. The process then starts again adding values until the array is full which will be 1 more value then recreating the second array empty and the length of the first array + 1. This is my attempt at creating this but I have run into multiple problems where I get only the last value I added and the rest of the values are null:
public class MyArrayList {
public Object arrayList[];
public MyArrayList(Object[] arrayList) {
this.arrayList = arrayList;
[code]...
why my program doesn't work. Here's the code :
public test5 {
public boolean test(int grille[][]){
for (int i = 0 || i < grille.length || i++){
int max = grille[i][0];
for (int e = 1 || e < grille[i].length || j++){
if (grille[i][e]== max && max !=0){
solution = false;
System.exit(1);
[code]....
I get quite a few errors while trying to compile the BeerSong from the Head First Java book. I copied the text from another person that did the beer song on this forum and it worked as expected. What I can't figure out is why mine is not working when it looks like the text is exactly the same between the two versions. His works, but mine doesn't.
Here is the text and errors that I get:
public class BeerSong
{
public static void main (String[] args)
{
int beerNum = 99;
String word = "bottles";
[code]...
It's probably really obvious, like it usually is, but I can't figure out why I am getting these errors on multiple functions.
if (!client.lowMem) {
for (int l = this.onDemandFetcher.getVersionCount(2), i2 = 1; i2 < l; ++i2) {
if (this.onDemandFetcher.method569(i2)) {
this.onDemandFetcher.method563(1, 2, i2); //Error
[Code] ....
The error I get on this line of code is 'Custom may not have been initialized', but no matter what I do, the error sticks.
Custom.cacheIndex = (Custom.cacheIndex + 1) % 10;
final Custom Custom = Custom.cache[Custom.cacheIndex];
//^^^^^
I am making a simple mod/hack for a game programmed in Java. I located the .class file I needed and deobfuscated it and then decompiled it. After that I went in and made a very simple adjustment that I wanted to make. Unfortunately I can across a problem when trying to compile the file! The file won't compile because there are errors. The reason there are errors is because this is just one file out of an entire game. I know this my seem weird, but is there some way I can compile the file with the errors.
View Replies View RelatedI have the following code snipet and I get the following errors
interface expected here
[javac] private class fileFilter implements FileNameExtensionFilter{
[javac] ^
cannot find symbol
[javac] symbol : method fileFilter(java.lang.Object)
[javac] location: class gui.components.StartupDialog
[code]...
import javax.swing.*;
public class opt
{
public int code[];
public static void main(String[] args)
{
int xxx = 1;
[Code] ....
Where did I did wrong cus I keep getting these errors: What do I need to do to fix the errors?
F:>javac opt.java
opt.java:25: error: cannot find symbol
cd.checkDeclare<zz>;
^
symbol: method checkDeclare<String>
location: variable cd of type code[]
java:32: error: cannot find symbol
[Code] ....
4 errors