I need to write an arraylist to a file.
It gets filled all the time and when it gets too big I need to start writing it.
So I thought ... |
I am working on a class that is going to contain objects with a time stamp and multiple measurements. These measurements are usually taken from 08:00 and until 16:00 every weekday, ... |
In the Hidden Features of Java question, I was interested in the answer about instance initializers.
I was wondering how to modify this line :
List<Integer> numbers = new ArrayList<Integer>(){{ add(1); ...
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Why aren't ArrayLists generally implemented to be double-ended, which would support fast amortized insertion in the front as well as the back?
Is there ever a disadvantage to using the latter over ... |
I'm making a vertical shooter game and I am having trouble with collision detection. Collisions are detected through the Rectangle method "intersect", but in order to keep track of everything that ... |
my arraylistS in a covering arraylist behave like the same instance.
i manupulate one of them with
i=0; manupulate((ArrayList)theCoveringRootArrayList.get(i));
, and all the sub arraylists have become effected of the manupulation.
i did my homework ... |
I am writing a program where I am eliminating the players with the lowest score and than distributing their supplies among the ones that are still playing. And on the first ... |
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I've two different classes:
Cliente.java
public class Cliente {
private static String user;
private static String password;
public Cliente (String usr, String pass) {
...
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I'm trying to learn Java, and came across a problem on one of the exercises
listed in the book that I'm using. The exercise asks for me to make use of the
ArrayLists ... |
I have a Project class and I want that to hold projects that I want to be doing. I'm a jewelry and want to essentially have a file from each project ... |
In the project I am working on, I have a 2D ArrayList which represents some data:
private ArrayList<ArrayList<T>> data = null;
Now I need to return this ArrayList to some object, in order ... |
How to add tokens to an arraylist in java?
I want to add tokens to an array list.
StringTokenizer st = new StringTokenizer(line, ":Mode set - Out of Service In Service");
...
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So I was wondering if it was possible in Java to trace back up an Array List? Meaning, if I have something like:
Section aSection = new Section();
aMainSection.get(0).aChildSection.add(aSection);
Where 'aMainSection' and 'aChildSection' are ... |
So I had asked a question similar to this, but I don't think the answer I got worked with what I was trying to do.
Say I have this class:
Java Code
public class ...
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I'm getting an error when declaring this ArrayList as an instance variable in Java.
private ArrayList<char> correctGuesses = new ArrayList<char>();
The error:
Syntax error on token char, Dimension expected after this token
Can I not ... |
So for a program I am working on, I am trying to create a method which will parse through a text file. Using the values within the text file, create an ... |
In general to decalre the arrayList we can declare as below.
ArrayList Obj = new ArrayList();
This is correct only. But in our code we will not do like this.we do ... |
I have some torrent file with list of announce urls, f.e. this is the part of it:
announce-listll68:http://iptorrents.com:2790/b6d18a815ab4421a86de672d6833369d/announceel67:http://iptorrents.me:2710/b6d18a815ab4421a86de672d6833369d/announceel67:http://iptorrents.ru:6969/b6d18a815ab4421a86de672d6833369d/announceee
So here is one array with key «announce-list» which contains three elements (bencoded data, |
A lot of people have said that ArrayList.removeAll is really slow with large size arrays.
This article provides two optimized solutions to the ArrayList.removeAll speed, but requires implementing them ... |
I'm trying to run a program I have made in Java, but I don't know what is happening that it
is giving me the following error:
Exception in thread "main" java.lang.ClassCastException:
java.lang.String cannot ...
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I already asked this question and I got additional question about using
class I made myself.
see code below.
import java.util.*;
class Pair{
...
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Possible Duplicate:
Adding enum type to a list
I have an enum class:
public enum MyEnum {
ONE, TWO, THREE;
}
And in another class, MyClass.java, ... |
How can I store an ArrayList of graphics so that I can then call a drawString() command on a specific ArrayList position?
For example this is what I want but none of ... |
I have an interface defined as
interface listItem {
public String toString();
public String getUUID();
}
And a class (browseItem) implementing that interface. When I ... |
I want to check branchList wheter has same element or not, if same put branchList and tglList element separate arraylist and put that arraylist into another arraylist,
The result I want ... |
Is it true to say that Java generics are all late binding ? Is an ArrayList type ignored until runtime ? Why is it ? Thank you.
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Ive been trying to work this out for a few hours now, but am stuck, hence I am coming here for some help.
N.B. I am using BlueJ, to construct these classes, ... |
I have an array list of a array list and I want to make a separate view of it that will filter certain things from it and store it somewhere for ... |
I have some code that I believe to run in O(n), however when I time it, it seems to run in polynomial time. I'm trying to process ~200,000 records, so ... |
Did some searching before asking, some not-so-reliable sources suggest that there's an underlying Object[] array.
Is it as simple as that? i.e. it handles resizing when necessary, maybe does a few tricks ... |
Can anybody tell me how to persist the ArrayList of java beans. If I have update the bean value update value should come
ArrayList temp = new ArrayList<AttendeeListBean>();
ArrayList getValue=AttendeeListModel.getAttendeeDetailContent();
System.out.println("getValue"+getValue.size());
if(getValue.size()<1)
{
attendeeContent ...
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Hello again fellow programmers.
so I'm creating a program that allows users to specify the type of insurance cover they want as part of an insurance policy.
Since their is only 4 ... |
So i have two questions here.. I have an object here that is an arraylist and for this case let's call it "Car".
I have made 2 of them (Car car1 = ... |
I have a table that I made by taking array list and storing it into another array list and it is composed of strings and doubles. Now I want to apply ... |
I have a multidimension arrayList and I ask the user for a formula and than I evaluate it. The problem is that I get user input like this:
((a1+a2)/12)*a3
the ... |
I have some pieces of C++ code that store objects in CObArray. I want to re-code the same pieces in Java using ArrayList to store the same objects. Will there be ... |
Is it possible to draw a polyline by passing the method an array list of Point values? something like this:
ArrayList<Point> projectilePoints=new ArrayList<Point>();
Projectile p = new Projectile(11, ...
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For some reason, I'm drawing a blank on this one. I have an ArrayList that contains CDs (some of them identical in name) and I want to print a String that ... |
I have an arraylist<interface>
Objects get added to this list in a for loop. I would like this arraylist to be empty each time the method is called.
Here is the code:
The ... |
I had the impression growing out of the applications by my work that when I define an ArrayList attribute in a class in Java 7, it is not necessary to initialize ... |
I'm trying import CSV file to Arraylist using StringTokenizer:
public class Test
{
public static void main(String [] args)
{
List<ImportedXls> datalist = new ArrayList<ImportedXls>();
...
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I want to ask a question about arraylist. In my program I defined an arraylist and an user defined object. The problem is when I want to add an object to ... |
I've got a very strange error, that would like to share with you.
I've the following code (simplified):
public ArrayList<String> al = new ArrayList<String>();
public void doSomething() {
int size = al.size();
...
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Prompt the user for a list size (e.g., N = 10,000).
Create an ArrayList of the Integers from 1 to N, in random order.
I think the best approach to create this is ... |
I am using Betwixt to output XML from a Java class, using .betwixt files to configure the mapping.
I am required to output some XML like this ( I have to conform ... |
I have an ArrayList that I am adding objects to. Objects are added by using a textbox.
The problem I have is when user enters a value into the ... |
I have some classes (Car, Motorcycle, Train ... etc) that extends from class Vehicle.
From another Class I need to create an ArrayList of Classes for access only to those that inlude ... |
I am a beginner to java, and need some help.
I am trying to convert an Abstract Data type Foo which is an associated list to an Arraylist of the strings B. ... |
I'd like to add (using the mathematical term) two Integer ArrayLists in Java, as well as divide them.
How would I go about this algorithmically? I can't for the life of ... |
I have a HashMap called examList which stored exam grades of each course a student took. The key of this hashmap is courseID, and the value is an array list gradeList ... |
I would like to represent matrix-like data in a suitable data-structure in Java. The dimensions of this matrix depend on user-input. One way would probably be to use a "magic" max-constant, ... |
I am currently using an Iterator to output an array list but I want to output it all on one line. I think my best bet would be to use a ... |
I am trying to print out the concordance from a txt file and im using a scanner to read the file below i seem to be have a problem putting the ... |
I'm new to programming and I'm looking for a simple answer to build my foundation of understanding Arrays. I've used google and searched this site.
After a bit of trial and error ... |
So the problem I'm working on solving involves an array list of array list of integers
. What is known: The number of elements in each ArrayList of integers. What ... |
I am new in Java.
Now I want to generate an ArrayList containing some values.
"Circle","blue","red","yellow","1","2","3","4"
How can I code this. I found some tutorial from internet. Only int or string accepted? How about ... |
Basically I have a team class, which has an array list that store the players in. In the driver class theres an arraylist that stores the teams.
Anyhow I've worked out how ... |
I am building an application with a Room class which is abstract and a Standard class which inherits from Room. I have then created a Hostel class. Within the Hostel class ... |
As I can see from the code you have provided, all is ok, you have added the entry. But maybe you are deleting the elements later on? Please provide code for ... |
rotaryfreak Hi all, Is it possible to create an ArrayList which will accept any object from the number class? i have tried something like: ArrayList userList = new ArrayList |
Just in case you're wondering... All the information you need on the ArrayList and any other Java class can be found in the Java API Documentation. This resource should get you ... |
It's supposed to print a summary of transactions for each account but it doesn't. I think the status is a problem but I can't follow why it won't store and print ... |
P: 2 jeffery123 I am new to java and I need to create an irregular polygon class that takes in an array list of Point2D.Double objects, constructs and initializes the points, ... |
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the connector public ArrayList getAllAdresses (UserBean u){ if (con == null ){ setupConnection(u); } ArrayList adressList = new ArrayList(); try { AdressBean ab = new AdressBean(); stmt = con.createStatement(); rs =stmt.executeQuery("Select * from BO_ISERIES.pfadress"); while (rs.next()){ ab.setFirstName(rs.getString(1)); ab.setLastName(rs.getString(2)); ab.setTitel(rs.getString(3)); ab.setAdress(rs.getString(4)); ab.setZipCode(rs.getString(5)); ab.setCity(rs.getString(6)); ab.setTelephone(rs.getString(7)); ab.setMobileNr(rs.getString(8)); ab.setEMail(rs.getString(9)); adressList.add(ab); System.out.println("Real one : "+ ab.getFirstName()); } Iterator it = adressList.iterator(); while (it.hasNext()){ AdressBean wb = ... |
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Lets start with the Servlet Code.... package myPackage; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.*; import java.util.*; /* * Created on Nov 20, 2007 * * TODO To change the template for this generated file go to * Window - Preferences - Java - Code Style - Code Templates */ /** * @author bmartin * * TODO To change the ... |
As I am writting my Beans I wonder whether you shouldn't use an ArrayList (or other collections) as properties of the Bean. The reason why is because I believe that the actual object contents of the ArrayList are hidden anyone else using the Bean. I would think it more appropriate to convert to a normal array before adding to your Bean. ... |
Hi Ranchers, I have a requirement where I am having around 12 parameters to be passed to the servlet from a JSP and then to the DB from the Servlet Now My question is how can i use an ArrayList to do this task of updation? Like say i want to store all the values in an ArrayList and then update ... |
Here is the answer with an example import java.util.*; public class myArrLst { public static void main(String[] ars) { ArrayList arlst1 = new ArrayList(); ArrayList arlst2 = new ArrayList(); //lets add some elements arlst2.add("4"); arlst2.add("5"); arlst2.add("6"); //Line X arlst1.add("4"); arlst1.add("5"); arlst1.add("6"); arlst1.add(arlst1); System.out.println("Size of list 1 " + arlst1.size()); System.out.println("Size of list 2 " + arlst2.size()); //Now the trick. There is ... |
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Hi, I am creating a program that makes a list of products that are used to create orders which are added to an orders queue. The thing is I don't know the first thing about arraylists and just can't understand what I need to do. This is my code so far:- package myprojects.burgerbararraylista; import java.awt.*; import java.awt.event.*; import java.util.*; class BurgerBarArrayListA ... |
Hi, I have a problem with the code below:- import java.util.*; //Needed when we use ArrayList /** * Order class. * * @author Ian Martin * @version 14.9.4 */ public class Order { private ArrayList Orders; //Will store references to Reservation objects //Constructor public Order() { Orders = new ArrayList(); //create an ArrayList object } //Add a Order to the Order ... |
Hi, When I use ArrayList in my program, it is working fine for small no.of objects which I'm going to add. But, when I come to add many objects say around 444444 (as my appication demands), I'm getting error "java.lang.OutofMemoryError". As I debugged my code, I could come to know that the problem is with ArrayList. Though I specified the initial ... |
Parse the String and create the ArrayList yourself -- reflection cannot do that. Then you can use the set(Object, Object) method of the Field to set the value of the array list -- set(target, arrayList). Alternatively, you caould use java.lang.reflect.Method to call your setLabels methods instead of using the java.lang.reflect.Field [ December 08, 2004: Message edited by: Joel McNary ] |
A little background about what I am trying to do may be in order. I work on several forums specializing in malware removal. The malware we remove tends to be weeks ahead of commercial applications catching up, so we come up with our own tools for analysis, etc. In the process of coming up with new fixes, we frequently infect our ... |
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Hello! ArrayList ar = null; HashSet hs = new HashSet(); I have an ArrayList of HashSet objects and i'm wondering how to reference a value in those combined objects! For instance, after loading the HashSet hs object, hs.add(val), i then assign that HashSet to the ArrayList, ar.add(i,hs)! So when using these combined objects to validate data, i'm wondering if there is ... |
Hi guys! Just a quick problem I have here. Basically I have an ArrayList of ArrayLists of some object. So it would look something like this: [ [1,2,3], [4], [5,6,7,8,9], [10,11] ] Now I want to get every possible combination of elements, selecting at least one from each arraylist. So I'd need: [1,4,5,10], [1,4,5,11], [1,4,6,10], [1,4,6,11].... [3,4,9,11] But my problem is ... |
Hi All, I have an ArrayList of two datatypes like String, float, while trying to retrive the actual values of these, I do the following Iterator iter = myArrayList.iterator(); while(iter.hasNext()) { String s = (String)iter.next(); } And obviously, this throws the java.lang.ClassCastException. Now my question is as to how to retrieve the actual values of my Strings and floats from this ... |
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Hi, I have a small problem.... I have got an arraylist of records say course details of a student. The status of courses is different. e.g suppose he is taking Java course the status will be in progress...for someother course the status will be completed or scheduled, etc.... I need to show to the user count of courses in each status...how ... |
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Hello, For the past week or so, I've been writing a program to transfer records from one database to another. I've been writing it with Eclipse, and can run it, and it works, and everything is just dandy. HOWEVER, if I try to compile at the command line, I get the following Fun: C:\BlahBlahBlah\BlahBlah\Blah>javac *.java -Xlint:unchecked DMUtil.java:46: warning: [unchecked] unchecked call ... |
Hi, I have a java class called myObject with three properties like prop1,prop2,prop3. I have another object called objectslist with an arraylist of myobjects as its properties and objlistprop. myObject{ prop1; prop2; prop3; } Objectslist{ arraylist myobjects prop2 } in my jsp I want to update prop1 of my object where myobject is [objectlist.get(i)] ith element of the list. Thanks, Krupa ... |
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First, consider that a hundred is a small number, by most accounts. Second, you have to specify what issues you're looking at. Appending items to the end of an ArrayList is very fast -- the technical term is "amortized constant time," meaning it's more or less independent of size, on the average. Accessing an item by index is also fast -- ... |
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Hi all, Im new to java. Im trying to use an ArrayList- as a private member, where Item is a class that I built. Basically, in main when I add an item to a local ArrayList it works fine. But when I call a method in a class that has an ArrayList as a private member and I try to add ...
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Hi all, i have an ArrayList where in there is a blank objects in between the String Objects in ArrayList. i Want to know how to get rid of this when i copy to another ArrayList. The Code chunk which i tried is as follows --------------------------------------------------------------------------- ArrayList l; for(int z=0;z |
which of the following statements are true of the ArrayList class? 1 It can store primitive or references as elements. 2 It implements the List interface. 3 It has a get(int index) method which returns the element at the specified position in the list. 4 The elements are ordered but not sorted. pls. let me know the explanation for the correct ... |
//Convert the int to String aList.add ( "" + rs.getInt ( "boat_id" ) ); //Convert the int to String aList.add ( String.valueOf ( rs.getInt ( "boat_id" ) ) ); //Fetches the integer as String from database aList.add ( rs.getString ( "boat_id" ) ); //Creates an Integer object and stores it aList.add ( new Integer ( rs.getInt ( "boat_id" ) ) ); ... |
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I have a class and an ArrayList inside the class. I am updating the arraylis from a method updateArrayList() like updateArrayList(int x) { this.dbList.add(x); } And in main() i am trying to access the same arraylist. class testClass { public ArrayList dbList; public static void main(String args[]){ testCalss testObj = new testClass(); for(i = 0; i < 10; i++) { testObj.updateArrayList(i); ... |