I ve got a 2d array and I want to cast it in an 2d arraylist. I ve create a function that cast an array to arraylist. My problem arises, when I tried to parse the whole 2d matrix to the arraylist. I use the following code:
Java Code: double sums[][] = computeSums(lab, projections);
ArrayList<ArrayList<Double>> lists = new ArrayList<ArrayList<Double>>();
ArrayList<Double> nu = new ArrayList<Double>();
System.out.println(sums[0].length);
for (int i = 0; i < sums.length; i++) {
The problem is that only the first matrix sums[0] is copied to the 2d arraylist sums.length times. How is is possible to store all the different sums matrices to the arraylist??
I'm actually trying to complete the excersise of the Servlets and JSP book in page 303 but I'm getting the following error in Eclipse Cannot cast from String to ArrayList(JSP).Here is the code
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <%@ page import="java.util.*" %> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Hobbies Sharing</title> </head>
[code]...
The error as it appears in line <% ArrayList al = (ArrayList)request.getParameter("Names"); %>
I'm making a program for my class's chapter on classes. I need to make a program that makes a grocery list using an array. Here's the assignment from the book.
Write a class named GroceryList that represents a list of items to buy from the market, and another class named GroceryItemOrder that represents a request to purchase a particular item in a given quantity (example: four boxes of cookies). The GroceryList class should use an array field to store the grocery items and to keep track of its size (number of items in the list so far). Assume that a grocery list will have no more than 10 items. A GroceryList object should have the following methods:
public GroceryList() Constructs a new empty grocery list. public void add(GroceryItemOrder item) Adds the given item order to this list if the list has fewer than 10 items. public double getTotalCost() Returns the total sum cost of all grocery item orders in this list.
The GroceryItemOrder class should store an item quantity and a price per unit. A GroceryItemOrder object should have the following methods:
public GroceryItemOrder(String name, int quantity, double pricePerUnit) Constructs an item order to purchase the item with the given name, in the given quantity, which costs the given price per unit. public double getCost() Returns the total cost of this item in its given quantity. For example, four boxes of cookies that cost 2.30 per unit have a total cost of 9.20. public void setQuantity(int quantity) Sets this grocery item’s quantity to be the given value.
I have the assignment mostly done, but the JUnit test case our teacher gave us to test it tests add() an array instead of an array list. For this reason, I need to change my program to use an array. My code is below.
import java.util.*; public class GroceryList { private ArrayList<GroceryItemOrder> list; int num; public GroceryList() { list = new ArrayList<GroceryItemOrder>(10);
So I'm trying to write a method which returns the number of vowel characters in arraylist. My idea is to convert the arraylist element by element to array each time iterating through the array counting the vowels of that element. When I started I immediately got an error(surprise, surprise). Excuse me if the problem is too simple, but I am very new to programming.
At line 9 I get the following error "Type mismatch: cannot convert from String to int". I want to get the element at this position, not to convert to int..
ublic class One { public static void main(String[] args) { ArrayList<String> bla = new ArrayList<String>(); bla.add("aaa"); bla.add("brr"); bla.add("unn"); } public static ArrayList<String> averageVowels (ArrayList<String> list){ String[] arrListWord = list.toArray(new String[list.get(0)]); return list; } }
package com.practice; public class Car { private String name; //name of the car private String modelName; //Name of the model private int year; //The year car was made in private int speed=0;
[Code] ...
It wont let me copy it into a array is there any solution to this.
I have a text file which contains to integer values I need to retrieve for each item (total of 56 items in the file). One is an item number, the other the weight ("Item: " + number + "Weight: " + weight). I am trying to build an array list that will add each set of data to it. I know that when I add the item array to the arraylist it is storing the array variable and not its contents, so is there a way to easily copy that data array to the array list?
Im trying to loop through a hashmap of objects. They are defined as People objects. People has two subclasses , Instructor and Student. As I am looping through the map of People, I am searching for class Instructor. If I find it, I want to access its method getDepartment in a println by casting to Instructor. When I do I get a runtime error:
Exception in thread "main" java.lang.ClassCastException: java.util.HashMap$Node cannot be cast to uStaff.Instructor at uStaff.PersonApp.menu(PersonApp.java:108) at uStaff.PersonApp.main(PersonApp.java:21)
//Instantiate the different Person, student and instructor objects Person thisPerson = new Person(01,fName,mName,lName,email,ssn,age); Student thisStudent = new Student(02,"Stacey","Marie","Morgan","smorgan@gmail.com","213-45-6789",20); thisStudent.setMajor("music"); Instructor thisInstructor = new Instructor(03,"Joe","Douglass","Wells","joe@drumhaven.com","555-98-3029",46); thisInstructor.setDepartment("Computer Science");
i am to add jpanels to an arraylist such that it forms a grid like a 2d array. when i add the first colunm and have to iterate and store the next sequence of jpanels it still stores it in get(0), instead of get(1).
I need to create a program that uses ArrayList to store integers the user inputs, then scan the array for the largest number. I would also like the user to be able to exit this loop if the number 0 is entered.
As you can see below, I'm not sure how to correctly exit the do-while loop. I found this on another forum, but it does not work.
Java Code:
import java.util.*; public class array { public static void main(String [] args){ ArrayList<Integer> list = new ArrayList<Integer>();
I'm trying to build a monopoly like game, and atm I'm trying to find way how to build the Community and Chance chest cards. so far, my logic is
1-create an ArrayList of cards with a given order
2-for a given number of times(for loop) generate 2 random numbers ,which will be the parameters for Collection.swap().
3-swap.
here's the code for the shuffler Button
shuffler.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { for(int i=0;i<shuffeledMessages.length;i++){ int randoma=(int)(Math.random()*4); int randomb=(int)(Math.random()*4); Collections.swap(myMessages,randoma,randomb); } } });
For now things seem to work pretty ok, but I'm wondering if this is a good and efficient way to shuffle a card chest especially in case of large number of cards. plus, I'm not sure what would be a good loop count for effective shuffling, in my case I used i<arraylist.size
When does an internal cast actually happen? I am aware that compound assignment operator do an internal cast. Does it happen in Assignment 1?Assignment 2?Assignment 3?Assignment 4?
Java Code:
public class Parser{ public static void main( String[] args){ byte b=1; short s=1; int i=1; s=b;//Assignment 1 s<<=b;//Assignment 2 b<<=s;//Assignment 3 s +=i;//Assignment 4 } } mh_sh_highlight_all('java');
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Boolean at javax.swing.plaf.synth.SynthTableUI$SynthBooleanTa bleCellRenderer.getTableCellRendererComponent(Synt hTableUI.java:731) at javax.swing.JTable.prepareRenderer(JTable.java:573 1) at javax.swing.plaf.synth.SynthTableUI.paintCell(Synt hTableUI.java:684)
I want to write formatted output on a notepad file using ObjectOutputStream but I am not getting it in human readable formatted form
Here is my person class
public class Person implements Serializable { private String firstName; private String lastName; private int age; public String getFirstName() { return firstName;
[code]....
I want to know how to use printStream.print() like method to write formatted output.
I am working on a program where I want the user to input multiple classes.
One int, and one String.
Can this be done? if so, how?
I have a tried to get input from both, like in the code below:
Java Code:
import java.util.Scanner; public class ForumFlowchart { public static void main(String[]args){ //Creating scanner. Scanner input = new Scanner(System.in); //Get information about job System.out.println("Type in Int"); int i1 = input.nextInt();
[Code] ....
If I keep my input in the same class, I get the error "Can not cast int to string". My question is, it is possible to get an input from both an Int and a String in the same program?
I have a msg object that contains an ArrayList<Integer> collection. However, in order to send the elements in the array over the udp socket, it needs to be sent as a byte[] array. So why am I using ArrayList<Integer> over byte array in first place? Well when I receive data from socket from embedded c program, I need to get an unsigned representation of the data, and thus I need to store it in integers, since bytes in Java are unsigned and unsigned chars in c that are greater than 127 will yield incorrect values in java. But when I send an ack back over the socket, I need to send the data back as bytes. So I convert the ArrayList<Integer> to a byte array:
Java Code: byte[] data = msg.toByteArray(); DatagramPacket response = new DatagramPacket(data, data.length, packet.getAddress(), packet.getPort()); public class Gprs { ... public byte[] toByteArray(){
[Code] ....
The problem is I get an "Cannot cast from Integer to byte" when trying to cast the integer to byte: data[i] = (byte)m_data.get(i);
I'm developing an application to track the status of a production flow-line and have hit a bit of a snag. When attempting to read saved data I run into this:
Exception in thread "main" java.lang.ClassCastException: flowline.End_Of_File cannot be cast to flowline.Operation at flowline.Station.checkLoadPreviousStationStatus(Station.java:91) at flowline.Station.main(Station.java:212) Java Result: 1
I've been reading up on different methods to saving and retrieving data and have decided ObjectInputStream would be the best option.
The save method works fine, I opted to use a EndOfFile class to determine when I've reached the end of the input stream. The problem is, when my loop encounters this object, it doesn't terminate the loop.
public void checkLoadPreviousStationStatus() throws FileNotFoundException, IOException, ClassNotFoundException, EOFException, TempArrayOutOfBoundsException{ Object loadOpn = null; End_Of_File eof = new End_Of_File(); File f = new File(fileName);
[Code] .....
The Operation cast is a cast to the objects my LinkedList contains. The highlighted line is where the exception occurs.
I am getting "Type safety: Unchecked cast from Object to LinkedList<EventData>" in eclipse for a piece of code stated below
public LinkedList<EventData> loadFromFile(File file) { queue=new LinkedList<EventData>(); //Some piece of code return (LinkedList<EventData>)queue.clone(); //--->getting warning here }
I know that because clone() method is returning Object, hence compiler doesn't have type information that's why showing warning. I don't want to suppress this warning instead i want to fix it.
