Hello: I am working with the Bridge2Java API from the IBM AlphaWorks. Bridge2Java allows java to communicate with ActiveX objects under Windows. I need to work with the Bloomberg ActiveX object. The object allows you to extact data from the Bloomberg market data service. Refering to the code below. Is there a smarter way to determine if the object returned from ... |
Hi, I've created an object called MailMessage(dealing with javamail) with 4 attributes and a getter/setter method 4 each. I'm creating another class that creates an array of objects: MailMessage[] mail = MailMessage[messages.length]; the mail object contains null objects...... so a mail[i].toString() is a null pointer. can I create this type of arrays? do I have to implement an interface? thanks. |
I am working on a project for college and it has me creating an array of ten objects and giving nine of those objects references to one of two different classes in my program, and the last one is just a dud value. The classes that are referenced through the array (Fiction, NonFiction, and Book are all in a sub-directory) and ... |
Hello, I'm having a null pointer exception error when trying to create a JTable. I think this is because the 2-dimensional array i'm passing in to the constructor has not been propery initialized. I won't go into loads of detail here...but is there anything wrong with trying to do something like this: private Object[][] tableData; private JTable table; public Object[][] getTableData() ... |
How can I add an Object to its Array??? When I create an instance of a Class and try to assign it to its array it gives me a Null Pointer Exceptions .... the line below in BOLD is where I get the exception. Is this legal in Java??? if Yes, why am I getting a Null Pointer Exception, or is ... |
An array of any type is an Object, yes -- an array is an instance of a special synthetic class that extends, directly or indirectly, java.lang.Object, just like any other class. You can call hashCode(), equals(), toString(), and other Object methods on any array. The fact that an int[] is a class doesn't mean that "int" is a class -- it's ... |
is there a way without giving me the code, just giving me an explanation of how to put this data into an array that I can then serialize the array instead of just the member data. Is this clear? Thanks, Joe public class FamilyMemberWriter{ private ObjectOutputStream os; public void openFile(){ try{//trys to create new file os = new ObjectOutputStream(new FileOutputStream("FamilyMembers.ser")); }//closes ... |
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I was trying trying to write a method to check to see if an array was populated (doesn't have all null values), but I also wan the method to check two or more dimensional arrays. The method I have written uses getClass().getName() and checks whether the name begins with "[" but it seems a little hackish to me. Here is the ... |
HI when we define String s[]=new String[4]; then i dont understand in java class hierarchy,s[] object is a subclass of which class?? is it directly a subclass of Object class or any other class. Because in one of the books I read that all object arrays inherit from Object[]. Also I want to know lenght property of arrays i.e. s.length is ... |
Hi, As we know we can asiign a array boject to a same dimensional array object For ex: String[] array1 = {"one","two","three"}; String[] array2 = array1; The above looks obviously simple but is there any metho to check when the same is for a multi dimesional array reference. I get confused when we have something like this. Can someone share a ... |
Surely Tony's code only builds and initializes a one-dimensional array, where the question calls for a two-dimensional array. It looks as if the step you are missing is to call new for each "row" of the array. Here's my suggestion: class foo { String a; String b; public foo(String a, String b) { this.a = a; this.b = b; } } ... |
In Java "Bar aBar;" declares a reference to an object that must be an instance of Bar. (This is different than in C++.) To create a Bar object and have aBar refer to it, you must do something like "aBar = new Bar();". The same applies to arrays. Each element of an "array of objects" really holds a reference to such ... |
Hi!! Just go thru the code.if U r not clear I will inform U in much better way. class employee { int empno; String empname; double bas_sal; public employee(int empno, String empname, double bas_sal) { this.empno =empno ; this.empname=empname; this.bas_sal=bas_sal; } } public static void main(String args[]) { employee[] e = new employee[1000]; for(int i=0;i<1000,i++) { e[i] = new employee(i,"raajesh",25000); } ... |
Just to be precise that is not a 2 dimensional array, it is an array of arrays. There are some languages that support BOTH. A multi-dimensional array wuold be an array with more than one parameter in the single array: String[] myArray = new String[3x4]; //not possible in Java An array of arrays would be String[][] myArray = new String [3][4]; ... |
Is the statement in my subject line possible? Perhaps I am missing it in my Java book, but can you assign more than one object to an array? I understand that arrays are objects, etc., however take the following "object array" declaration/initialization: buildings[] block = new buildings[100]; This would take a "buildings" object and place it to an array, referenced by ... |
Hi, This is probably basic stuff, but it really doesn't stand out very clearly in any of the java tutorials I checked: I have a class like this (I've greatly simplified it, it's really not this rudimentary): class manifold { private int[] content; public manifold(int size) { this.content = new int[size]; } } Now I want to make an array of ... |
Hi, this seems like a trivial problem which has tied me into a knot. I have created an array of objects Object obj[] = new Object[23]; and i am added objects to this array. At run time i want to know the number of objects in this array. I tried the Array function getLength() as var = obj.getLength(obj); But the compiler ... |
Java is not a structured language. It is object oriented and we lack the structurs in one or another way. In C++, we can create an object array easily and can able to assign the variables so easily, even assigning the values of the member variables of an object array. In java, we will encounter NullPointerException if we try to assign ... |
Do you mean that one will be the name of the class and the other will be an object of that class? Object [][]myArray = new Object[][]; Then you can do WhateverClass myObj = new WhateverClass(); myArray[0][0] = "WhateverClassName"; myArray[0][1] = myObj; etc. [ February 05, 2002: Message edited by: Cindy Glass ] |
Below is code for a class Computer. MemoryChip is another class, it works fine. I'm having trouble trying to figure out how to work with the arrays of MemoryChip in the constructors and with method addAChip(). I don't like writing duplicate code, but maybe I'll have to in spots. Will the constructor have to call addAChip() twice, and addAChip() have to ... |
I am completely lost on this issue, so as much information I can get would be helpful. Is there an object that will hold several arrays? Then when I call that object, I would like to reference specific element from a specific array held within this object. Does anything like this exist ? I am just reading about Collections, but I ... |
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I have an application that has an instantiable Student class that creates objects that can store information about a student's name , major , credits earned and whether or not they're a senior. I have created set and get methods to get and change the information in these objects. I just created an array of 3 Student objects and I'm trying ... |
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While reading about Java I think I understand that there is something called an Array class which has methods and properties and then there is an array which is part of the Java language. I was taking a practice test and then looking at the explanation of the answers where they said an array has a "property" of "length". I thought ... |
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I am havin problems with the following code and have spent already spent hours but got nowhere. can somebody help me pls?? why is all the values in the element objects, equal to the last code entered. the code is Scores myScores[] =new Scores[10]; // Scores is class for(int i =0; i < myScores.length ; i++) { myScores[i] =new Scores(); System.out.print("Score ... |
hi all; i am trying to define an array of objects of class myLine but get the following compiler error DrawingApplet818.java [52:1] ';' expected myLine [ ] l = new myLine[5](); ^ 1 error Errors compiling DrawingApplet818. see the 4th non-comment line of applets paint() method. any ideas what i am doing wrong? thanx db /* * DrawingApplet818.java * * Created ... |
I have a collection class that creates an array of objects in the constructor. I have a class that contains set and get methods to get the information out of the array created. I have another method that searches through the array for matches to what the user types in. If a match is found, then a boolean value is set ... |
Basically I have created an object and this object contains all the attributes I need. How would I go about creating a array of say 10 of these objects. Also, can you name an object via a variable like Car myVariable myVariable = new Car (millage, engineSize, mpg, status, manufacturer, registration); Thanks... |
This one is easy. since x is declared inside the "for" statment, it falls out of scope once you leave the loop. you don't have braces after your "for" statement so, the only line that is part of your loop is the "tempBuyCar" line. that is the ONLY line being run over and over. so... when you get to the arrayOfCars, ... |
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Hi all, first post here. I've been having this problem and suddenly thought "Is this the equivalent of trying to fix my car trouble by experimenting with different types of gas, when the real problem is I've put the wheels on the roof...?". In other words, I'm wondering if my program design is just plain wrong. I've done some OOP in ... |
Hi Joe, Welcome to JavaRanch A quick administrative note, it is generally a lot easier if you place any sample code in UBB [code] [/code] tags. It makes reading the code much easier. Take a look hereto learn how to use UBB In addition to Jasons comment, there is another "problem" in your code that should be pointed out so you ... |
You can just use an instance of the class to access its array. Consider this. class1.java ------------ public class class1 { public String firstName; public String lastName; class1(){}; class1(String firstName, String lastName) { this.firstName = firstName; this.lastName = lastName; } } class2.java (Create an array c1array of class1 objects) -------------- public class class2 { public class1 c1 = new class1("Amit", "Saini"); ... |
I need help I am working on a program for class. I need to Pass data in a object array from my Main Driver to class in a package but I can get my code to work. I need all the help I can get. From some reason when I loop back thru the array I alwasy get to last thing ... |
Hi Friends, I have a Object[][] array of (Integers,Strings,Double,Long etc).I just need to find out the class of each element type.I am trying something like this,which I am sure is wrong: for(int i=0;i |
this is my code public class Event{ public String eventDate; public String eventName; public String eventDescription; public String eventLink; public String eventContact; } public class ObjectArrayTest{ public static void main(String [] args){ Object[] myArray = new Object[3]; Event etest = new Event(); etest.eventDate = "test"; etest.eventName = "test"; etest.eventDescription = "test"; etest.eventLink = "test"; etest.eventContact = "test"; Event etest2 = new ... |
Hey, I'm trying to write a program which reads in a sequence of lines, containing a name and telephone number and sorts it into an alphabetically ordered telephone directory. I was just wondering if anyone would be able to tell me how I could read in an unlimited amount of input...?? Thanks in advance... |
In a program I have to create a MyClass class a HisClass class and also a main program class which generates output.in MyClass there are names passed to it from the main class using the JOptionPane,24 in all .In the HisClass I have to create an array of MyClass objects and assign each object it`s individual value ie the name passed ... |
I am studying for my Certs and keep seeing posts and things about the power of using arrays of different objects that implement the same interface. I haven't written or seen code that does this and I can't understand the power of this. Why is this one of the most powerful uses of interfaces? I get the feeling if someone would ... |
L3 is correct because all arrays implictly extend Object. This means that Integer[] "is an" Object. L5 causes an error because arrays DON'T extend Number or any other class. All arrays extend Object directly. L8 is okay because Integer extends Object, so you can assign an Intger[] to an Object[]. However, L11 causes an error because a is an int[]. Since ... |
Hi in the programe below when i run it prints to the screen this: student.assignment.Student@108786b student.assignment.Student@108786b student.assignment.Student@108786b i think it is some thing to do with the code students[index] = studentObj; in the addStudent method in the storage class can any one inlighten me on to why this is happing? here is the code: package student.assignment; public class Student { private ... |
import Project_Table public class Query_Class() { Project_Name_Query(int xtype_ID, class Project_Table) { Array Project_Table = new Project_Table[] Statement stmt = con.createStatement(); ResultSet rs = stmt.executeQuery("Select Project_ID, Project_Name FROM Project_Table WHERE Type_ID = " + Integer.toString(xtype_ID)); int i = 0; while(rs.next()) { Project_Table[i].Project_ID = rs.Project_ID; i++; } } public class Project_Table { public static void main (String args[]) { string Project_ID = null; ... |
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i am supposed to create a simple program that prompts the user to enter an integer and then asks the user to enter that many values stored in an array. Then they are printed out...then the order is reversed and printed again. It's working fine my only problem is when i prompt the user to "Enter x values:" the number x ... |
because a bird is an animal, but it is not a dog. in other words, your array niceAnimals of Dogs can ONLY hold Dogs (or sub-classes of Dogs). but your array of Animals MIGHT have a bird, a fish, or a cockroach in it. they are all animals, so they all go nicely into it, but they are not Dogs. [ ... |
hi all, i got an array question. i'd like to create a new array and append nodes to it in a loop, like this: //ch contains some X3DNodes MFNode oldChildren = (MFNode)parentX3DNode.getField("children"); //create a new X3DNode X3DNode newChild = new X3DNode(); //create new Array on which newChild and all X3DNodes from oldChildren should be stored X3DNode[] allChildren = new X3DNode[ch.size()+1]; // ... |
hello, i have created an array or my own named Store. i want to create an array of objects using this class. iv used Store[] s=new Store[2]; then im assigning values to the elements using a for loop for(int i=0;i<2;i++) { s[i].setXXX(parameter);} but im gettin a null pointer exception here on s[i].setXXX line. Please tell me how to correct this part. ... |
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Hi, When I do array of primitive elements initialization like int[] key={4,5,6}; and in the static main method, I created System.out.println(notes.key[0]);-----------it gave output 4 But ,in object references array elements initialization Dog[] myDogs={puppy,new Dog("Clover"),new Dog("Aiko")}; In a static main method, I created System.out.println(notes.myDogs[0]);//--------------it just gave some address. 1.Why is it giving address? 2.To get the result puppy,what should I include and ... |
I have created a object of a class and stored it in a arry of Objects. when i am trying to access any method of that class, i am able to call it using reference of that calss, but not able with the arry element, where i have stored that ref in arry. ie. Trial t = new Trial(); t.example(); It ... |
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Hi everyone, Please bear with me for a while as i need to ask a rather silly question. Does anyone know how to decalre an object of arrays with arguments. See the below code public class JTest { public JTest(String w) { System.out.println(w); } public void prt() { int i = 0; for(i=0;i<5;i++) { System.out.println("This is prt ouput " + i); ... |
// This creates an array of Student objects, // but all the 10 elements are initialized to null. Student[] array = new Student[10]; // Now you have to create each of the Student objects in the array. for (int i = 0; i < array.length; ++i) { array[i] = new Student(); } |
Thanks to two of you who responded to my last question, I was able to succesfully create an array of student objects. However, I am having a problem passing it to another class. I have two classes you see.... StudentApp.java - this creates the array and inputs data into it Student.java - this manipulates student objects. What I want to to ... |
Not sure I follow. Do you mean something like this? class MyBean { private String name; public MyBean() { name = "?"; } public void setName(String newName) { name = newName; } public String getName() { return name; } } public class BeanArray { private static final String[] NAMES = {"Lima", "Pinto", "Black", "Garbanzo"}; public static void main(String[] args) { //Declare ... |
Can a method be written to swap two objects? void swap(Object obj1, Object obj2) { ??? } And how about if we want to pass primitives? void swap(int a, int b) { ??? } I don't think there is any way to do this. But how and why Java can be so cruel? |
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The array is made up of five variables that can refer to A objects. Each of these five variables is null when you construct the array. If you want five objects, then you must construct each one individually and add it to the array -- i.e., ob[i] = new A(); Note that rather than having exposed member variables and setting them ... |
Create an array of object references of the class you created in Exercise 2, but dont actually create objects to assign into the array. Code from exercise 2 class ch4ex1{ ch4ex1(){ System.out.println("Constructor"); } ch4ex1(String str){ System.out.println("Constructor" + str); } public static void main(String args[]){ ch4ex1 c = new ch4ex1(); ch4ex1 e = new ch4ex1(" test"); } } Here's what I thought ... |
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Sample s = new Sample(); Sample [] s = new Sample[4]; In first case, reference s is created on stack and object Sample is created on heap. In second case, how does it work ? is it like that s1, s2, s3 , s4 are created on stack and objects they refer to are created on heap ? Then where is ... |
Hi Lets say i have an object A with id as an attribute and its type is int. I fill the array list with the A type objects. i want to check if the id in the object A exist. Is there a way i can do it without looping through the entire collection, get the object A and comparing A.id ... |
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an serious doubt how to call a method using array of objects? here class bank have b1[] as a array of object... i need to call method get() for two objects b1[0].get()? it showing error....public static void main(String[] args)throws IOException { String str; int a,x; [B]bank[] b1 = new bank[2]; bank[0]=new b1.get()[/B]; do { System.out.println("enter your choice:"); System.out.println("1.deposit 2.withdraw 3.display"); DataInputStream ... |
according to me the output of following code public class Test { int a; int[] b; public void f() { a = 0; b = new int[]{1,2}; change(b, a); System.out.println(a + " " + b[0] + " "); } public void change(int[] x, int y) { y = 10; x[0] = 10; } public static void main(String[] args) { Test obj ... |
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In Java, arrays are objects, it can be created dynamically and can be assigned to variables of type Object. All methods of class Object may be invoked on an array. A variable of array type holds a reference to an object. Declaring a variable of array type does not create an array object or allocate any space for array components. It ... |
Hello All, I have this Array of an object type where the object contains three elements that constructs as a key. SomeData[] arrSomeData I will have multiple occurences of this object. I need to make sure there are no duplicates based of this key value. If such duplicate is found an exception is raised. I can do it using nested loops ... |
Hi, could someone please help me to solve this problem related with declaring an array of objects and then calling a method from the object... I created an array of objects: InputNeuronObject[] InputLayerArray = new InputNeuronObject[64]; In the main method I then did a loop and I tried to call the method inputLayerArrayInitialise() to initialise the objects of the array, but ... |
Dear All, I've an challenge with casting an 2-D array to an object reference. When I'm trying to use the object reference index values to cast it into an one dimensional array, it throws compile time error whereas i am able to cast that object reference to another 2-D array. This is my code class TwoDcheck { public static void main(String[] ... |
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import java.io.*; import java.text.DateFormat; import java.util.*; public class Fillup { double[] b; Fillup(double... b) { this.b = new double[b.length]; for(int i = 0; i < this.b.length; i++) { this.b[i] = b[i]; } } public String toString() { StringBuffer s = new StringBuffer(); for(double i: b) s.append(i+" "); return s.toString(); } public static void main(String[] args) throws Exception { Fillup[] fillup = ... |
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Hello again, I need to know how to populate an array object in java. Here is my code so far: import java.util.Arrays; public class Transcript { Course student = new Course("COP 2235", "A"); String courseID; int studentID; String studentName; int count; Course theCourse[] = new Course[9]; } I want to fill each level of the array with a string for the ... |
I am trying to create new objects named cpu0, cpu1, ..., cpu8. The objects will be "Thread1_a" objects. I am getting a syntax error when I try to create the objects. Any help would be really appreciated!! - Jeff // Ttest1.java class Ttest1 { public static void main(String argv[]) { System.out.println("Howdy"); String cpu[] = new String[8]; for (int i = 0; ... |
I tired the code and as Henry said .. no-arg constructors only it works with Constructors with args also. class Book{ int AccNo=100; String title="Head First Java"; Book(int x) {System.out.println("New Book created " +x);} } public class TestClassChap3 { static Book[] my_books1={new Book(3),new Book(2)}; public static void main(String args[]) { System.out.println(my_books1.length); }} |
i have started on this project that calculated the carbon foot print of a family. i have been working on it for a few days now. for the sake of not having to explain what i am trying to do i will simply post the instructions. 5. The program should be written in OOP format using a tester class. 6. For ... |
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Hello, I have a little bit of code here and what it is attempting to do is read a file into a arraylist then return the array object to another method/Class for testing I am just using a method later it will e a class. I can get the createObj code to work and but I have loss may way attempting ... |
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Hi, I'm using Deitel and Deitel to learn Java. (Great book!) I'm on the chapter of Arrays. In the book, it states every array object knows its length and stores in a length instance variable. Isn't an "instance variable" the same thing as a "field"? I went to Java's SE's API to look at the properties of the Array Class and ... |
myObject[] objArray = new myObject[10]; //alocates memory for 10 objects of type myObject. this would create 10 reference variables of type myObject but the value assigned to each will be null. hence these variables will hold the reference to objects only if we create Objects. like objArray[0] = new myObject(); //first object is created and the rf of this object is ... |
Declaring static fields in any class means those varibles can be accessed without instatiating object of that class. Example Class MyClass{ static declaration including objects or array or primitive.. } Static varible does not mean that you do not instantiate it.It means you do not require to instatiate the class in which they are declared however you need to create a ... |
public class Animal { private String name; //... public Animal(String inputName, int inputStrength, int inputDefence, int inputSpeed, int inputFlee) { name = inputName; //... } public void setName(String inputName){ //setter method name = inputName; } public String getName(){ //getter method return name; } //... getter and setter for other variables if needed } |
In the Java programming language arrays are objects , are dynamically created, and may be assigned to variables of type Object . All methods of class Object may be invoked on an array. int[] arr = new int[10]; here arr reference variable pointing to object of "Object" Class An array object contains a number of variables. The number of variables may ... |
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Hi there! I'm pretty darn green when it comes to Jva and programming as a whole. I am using a Java Course from MIT Open Courseware to learn it on my own. QUESTION: I am doing the Library assignment and my question concerns placing 4 different Book objects into an array, using a for loop. Right now the program outputs all ... |
Hi all. >.>b Another newbie here like this one; also studying Head First Java (second edition), also hoping to write apps for my new Android phone. I just finished chapter five, with the enhanced for loops and things, and I'm trying to write a test program that incorporates them. Only problem is, I can't seem to get it to do an ... |
Given the following 3 classes Animal, Dog, and Array in 3 separate files, I compiled them and ran only the Array class with the following results: line 42 output: protected Animal instance variable i = 1 line 46 output: Dog element = pkgb.Dog@45a877 My Questions: 1. Why wouldn't line 48 compile without the cast when line 42 did not need one? ... |
I'm creating a Connect Four program, and the first part of it prompts the user for the number of players. The minimum allowed is two and the max is four. Once that is determined, it then progresses to allow the users to input their names. These names need to be stored in an array (or arrayList, it doesn't matter). Here's my ... |
As JavaDoc describe, the method InputStream.read() Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the ... |
hey everyone. So i'm working on my own version of mineSweeper. My professor's explanation, even after several times asking, doesn't seem to quite click with me. In the following code, I have to implement the MineSweeper constructor and my needed instance variable in it. So I've been told the constructor is taking an array of GameSquare objects. My question is: how ... |