Launcher References Object Variable

May 22, 2015

So I set out to write a program that takes two things from user: Name and Age

Then prints out "Name is Age"

I went through using a "launcher" and having a proper object: [URL]

The class names are Practice and Practice Launcher because I just use a Practice file as a sandbox environment so I understand its not correctly named. I also understand my comments aren't great but I'm just trying to make it work.

Practice.java
public class Practice {
//constructor
public Practice (String a, int b) {

[Code]....

My Practice.userName doesnt reference the variable userName. Why is this?

Also y does this line need Practice twice?
Practice Practice = new Practice(userName, 45);

View Replies


ADVERTISEMENT

Practical Use Of Multiple Object References Pointing To Same Object

Dec 27, 2014

I am reading Head First: Java and got to Object References. In the book I got a little bit confused on what happens when two object reference's point at the same object so I wrote a small crude test, the below code. This of course clarified what happens but what I am interested in knowing is in what circumstances would you want to have two separate references for the same object when you could just use the original? Eg. v1

class ObjectValue{
int objVal = 1;
}
class ObjectValueTestDrive{
public static void main(String [] args){
// "Value of v# should be" refers to if it copied the given object values, instead of referencing the same object
ObjectValue v1 = new ObjectValue();
System.out.println("Value of v1 should be 1:" + " "+ v1.objVal);

[code]....

View Replies View Related

Object Pool Using Phantom References

Apr 19, 2014

I have to implement an object pool that uses phantom references to collect objects abandoned by client threads. This is what I have. I'm really not sure about this implementation.  
 
class ObjectPool<T extends CloneableObject<T>> {
  private Queue<T> pool;
  private List references = new ArrayList();
  private ReferenceQueue rq = new ReferenceQueue();
  private CloneableObject<T> prototype

[Code] .....

View Replies View Related

Modify Common Object References In Lists - MyArrList And UrArrList

Jan 29, 2014

"What happens if you modify the common object references in these lists, myArrList and urArrList ? We have 2 cases here: In the first one, you reassign the object reference using either of the lists. In this case, the value in the second list will remain unchanged.In the second case, you modify the internals of any of the common list elements - in this case, the change will be reflected in both lists."

I have written the following code, which tests the first case mentioned above, and i get the output as expected: myarrList remains unchanged. How can i test the second case ? My thoughts are ....'second case is untestable the following code, because String is immutable. I need to use StringBuilder or something else to write code for test of second case mentioned'.

ArrayList<String> myarrList = new ArrayList<>();
myarrList.add("one");
myarrList.add("two");
ArrayList<String> urarrList = new ArrayList<>();
urarrList.add("three");
urarrList.add("four");
System.out.println("ArrayLists setup");

[code]....

View Replies View Related

Object Reference Variable Unwilling To Be Reset To A Different Object Type

Nov 6, 2014

I don't understand why the object reference variable 'a' cannot be recast from a thisA object reference to a thisB object reference.Is it the case that once a reference variable is linked to a particular object type then it cannot switch object types later on.I am facing the Java Associate Developer exam soon and I am just clearing up some issues in my head around object reference variable assignment,

class thisA {}
class thisB extends thisA { String testString = "test";}
public class CastQuestion2 {
public static void main(String[] args) {
thisA a = new thisA();
thisB b = new thisB();

[code]....

View Replies View Related

Old Object Take Variable From New

Apr 30, 2014

I have a problem with my code. When, on strausParser class, i create the new object Beam i give him an array of Node object called "nodiestremi".

The problem is that when a Beam is created, the Beam created before take the Node of new Beam. Why it appends?

public class Main { 
public static void main(String[] args) throws NumberFormatException, IOException{
SetFile.setupWindows();
Structure structure = new Structure();
}
public class SetFile {
}

I get an output like this:

Import node complete
0 0 0 1
0 1 1 2
0 1 1 0
0 2 2 4
Import beam complete

and not like this:

Import node complete
0 0 0 1
0 0 1 2
0 0 1 0
0 0 2 4
Import beam complete

View Replies View Related

File Transfer But Cannot Load In Its Launcher

Feb 3, 2015

Okay I am having a problem I wrote some code to transfer a file from my server when requested by the client. The problem is that when the file which is requested is transferred the file cannot be open in its respected file launcher when clicked. The File launcher throws back this msg "My Issue It request the File but after the File is requested and stored on the Client Machine when I Hit the File to be Launch adobe says the file "Adobe could not open the File for it is not supported file type or because the file as been damage"

So i have two pair sets of code for original coded by me. Original code i had first Server

import java.io.*;
import java.net.*;
public class SimpleFileServer {
public final static String FILE_TO_SEND = "c:/Users/Acer/Downloads/COAFlags.pdf"; // you may change this
public static void main(String args[]) {

[code]....

View Replies View Related

Adding App To Launcher Using Android Studio

Feb 5, 2015

I am trying to make my first application on Android. I have never done it before. I am totally new at it. I want my app to show as an icon on the launcher but how to do it.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="net.graphicport.homeinventory" >
<!-- To auto-complete the email text field in the login form with the user's emails -->
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.READ_PROFILE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.INTERNET" />

[code]...

View Replies View Related

Java Virtual Machine Launcher

May 1, 2015

I created a program and am able to run it perfectly fine in netbeans/cmd. Then I made an .exe file with "Launch4j" and every time that I run the .exe file I get the following error: Java Virtual Machine Launcher: "A Java Exception has occurred."

Here in detail:

Exception in thread "main" java.lang.NoClassDefFoundError: edu/cmu/sphinx/util/props/PropertyException
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
at java.lang.Class.privateGetMethodRecursive(Unknown Source)
at java.lang.Class.getMethod0(Unknown Source)
at java.lang.Class.getMethod(Unknown Source)

[code]...

View Replies View Related

One Object / One Instance Variable - Different Values?

Feb 5, 2015

Let's pretend I'm working on an RPG. Like in all RPGs, there are items found all throughout the imaginary world. Each player and NPC can obtain an item. My question will concern those items.

In other words, I'd like to use instances of a class in multiple places of the code. Each instance will have its own, individual values of instance variables, with one obvious exception: itemQuantity should have a different value in playerInventory, npcInventory, etc. Also, I'd like a list of all items that can be found in the game. This list doesn't need itemQuantity at all.

class Items {
String itemName;
float itemWeight;
int itemQuantity;

[Code] ....

The question is: should I really make itemQuantity an instance variable of the Item class? It seems as though for each copy of the Item class I should create a separate copy with different value of itemQuantity, but that's not very efficient. Where is the error in my logic?

What's important is that there may be plenty items in a game and a player may be given power to create new items during the course of the game.

View Replies View Related

Searching ArrayList By Object Variable?

Oct 7, 2014

I'm almost finished my Bank Account exercise and I found myself stuck at the last part. Its asking me to add a method that asks the user to input the name of the account into which they want to deposit money, then search the ArrayList for that account. If it is found, the user is asked how much money they wish to deposit.

I already have my deposit method sorted so basically what I need is just searching through the ArrayList by the name variable. I assume its don't by iterating through with some form of for loop.Heres what I have:

import java.util.Scanner;
public class BankAccount {
private double balance;
private String name;
public BankAccount(double balance, String name){
this.balance = balance;

[Code]......

And the driver class

import java.util.ArrayList;
import java.util.Scanner;
public class BankDriver {
Scanner scan = new Scanner(System.in);
ArrayList<BankAccount> list;
public BankDriver(){

[Code]...

View Replies View Related

Virtual Machine Launcher - Java Exception Has Occurred

Apr 29, 2014

I developed a Java application and it works fine on my computer, but when i tried it on another computers, I have the following errors :

A window named Java Virtual Machine Launcher appears and it says "A Java Exception has occured".

My application don't even launch.

Here is the error lines, but I don't know what to do :

C:UsersAdministrateur_localserveurtimet>java -jar ServeurTimeT.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: TimeTracking/
ServeurTimeT : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)

[Code] ....

Java is up to date.

View Replies View Related

Link Objects And Calling A Variable Object Method

Jun 14, 2014

Say I have two classes, Author and Book, and I have 2 author objects and 10 book objects. I would like to know how to do two things:

1) Make some sort of connection that makes clear that author X wrote books A, B and F.
2) Call a method from a book object that is connected to an author.

Seeing as I don't know which books will be connected to an author, is there some way to call a method of an object bases on a variable object name? Something like call the getFirstPage() method for every book that is linked to author X?

View Replies View Related

How To Create File References

Sep 7, 2014

Is there any way to create file refrences so that it look's like there is a file in a directory while it actually is in a different directory?

View Replies View Related

Generics Wildcard Array Of References?

Jul 27, 2014

An array of references to a specific generic type is not allowed in Java.

e.g.,

ArrSpec<String> arrs[] = new ArrSpec<String>[10];

is not allowed though the type checkng and memory allocation can be done at the compile time itself.

Instead of this, Java allows to use Wildcard type array of references to a generic type.

e.g.,

ArrSpec<?> arrs[] = new ArrSpec<?>[10];

is allowed though the type checking, memory allocation and any type of values to be stored would be decided at the runtime.

View Replies View Related

How To Do A Deep Copy Of Objects That Contain References

Mar 21, 2014

how to do a deep copy of objects that contain references. I am specifically wanting to make a deep copy of a tree. Logically, each tree node contain references to its children nodes. Here is the basics of my node class

public class BSTNode implements Comparable, Serializable {
 
private String token;
private int count;
private BSTNode leftChild;
private BSTNode rightChild;

I know I must only be making a shallow copy because when I make a copy of tree1, called tree2, and edit tree1 the edits also appear on tree2. Here is my copy method within my BSTNode class

public BSTNode copy()
{
BSTNode obj = null;
try{
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(this);
out.flush();
out.close();

[code]....

When I wish to copy the entire tree, I call that above copy method from my BSTree class using the methods below. (I have 2 methods because this is a homework assignment that requires a copy method that calls a preorder traversal method)

public BSTNode copy()
{
BSTNode copiedTreeRoot = new BSTNode();
return copyTree(copiedTreeRoot,root);
 
[code]....

And further along when I make changes to tree1, tree 2 also changes. I have no clue what I'm doing wrong. I believe it must be somewhere in how I return the new tree or something.I tried this edit to my copy method, but it made no difference.

public BSTNode copy() {
BSTNode obj = null;
try{
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(this);

[code].....

View Replies View Related

Would Switching References Change Their Graphical Position?

Jan 19, 2014

So I have an array of objects, each with their own position, I tried switch the references in the array of two objects, then repainted (immediately), but the two objects aren't switching positions on screen...does this even work?

View Replies View Related

Difference In Variable Assignment Between Constructor And Variable Section

May 21, 2014

Given the case I have an object which is assigned only once. What is the difference in doing:

public class MyClass {
private MyObj obj = new MyObj("Hello world");

private MyClass(){}
//...
}

and

public class MyClass {
private MyObj obj;
private MyClass(){
obj = new MyObj("Hello world");
}
//...
}

Is there a difference in performance or usability? (Given also the case there are no static calls expected) ....

View Replies View Related

Are Terms Local Variable And Member Variable Comparable

Oct 27, 2014

The term "Local variable" is related to scope. That is a local variable is one which is defined in a certain block of code, and its scope is confined inside that block of code.And a "Member variable" is simple an instance variable.

I read in a discussion forum that when local variables are declared (example code below), their name reservation takes place in memory but they are not automatically initialized to anything. On the other hand, when member variables are declared, they are automatically initialized to null by default.

Java Code: public void myFunction () {
int [] myInt; // A local, member variable (because "static" keyword is not there) declared
} mh_sh_highlight_all('java');

So it seems that they are comparing local variables and member variables. While I think a member variable can also be be local in a block of code, isn't it?

View Replies View Related

Reference Variable - Create Another Variable And Set It Equal To First

Jan 11, 2015

Given a reference variable : Car c1 = new Car();

when we create another variable and set it equal to the first : Car c2 = c1;

we're pointing c2 at the same car object that c1 points to (as opposed to pointing c2 at c1, which in turn points at the car). So if we have code like,

Car c1 = new Car();
Car[] cA = {c1, c1, c1, c1};

are we doing the same? Are we creating four *new* reference variables, each of which points at the same car (again as opposed to pointing them at c1 itself)? I think so, but want to make sure I'm understanding this correctly.

View Replies View Related

How To Use Value Of String Variable Cel1 As Variable Name

May 23, 2014

I have a JFrame jf and JPanel jp on it. jp has five TextFields named cel1, cel2.. cel5. I wish to construct a String Cel + for loop index and run a for loop to reset the values of all the text fields using a single statement such as cel1.SetText("abc"). Similar things can be done in foxfro. How does one do it in java?

View Replies View Related

Equals Method - Take Object Reference And Return True If Given Object Equals This Object

Mar 28, 2014

Create an equals method that takes an object reference and returns true if the given object equals this object.

Hint: You'll need 'instanceof' and cast to a (Geocache)

So far I have:

public boolean equals(Object O){
if(O instanceof Geocache){
Geocache j=(Geocache) O;
if (this.equals(j)) //I know this is wrong... but I can't figure it out
return true;
}

else return false;
}

I think I have it correct up to the casting but I don't understand what I'm suppose to do with the this.equals(). Also I'm getting an error that I'm not returning a boolean... I get this all the time in other problems. I don't get why since I have to instances of returning booleans in this. "returns true if the given object equals this object" makes no sense to me. I assume the given object, in my case, is 'O'. What is 'this' object referring to?

View Replies View Related

Get Object Strings To Print In List So That User Can Select That Object To Manipulate Its Attributes

Oct 7, 2014

I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. I have an Array of objects that contains strings. How can I get the object's strings to print in a list so that the user can select that object to manipulate its attributes? For example, the user can select "Guitar 1" from a list and manipulate its attributes like tuning it, playing it, etc. I have a class called Instruments and created 10 guitar objects.Here is the code:

Instrument [] guitar = new Instrument[10];
for (int i = 0; i < 10; i++) {
guitar[0] = new Instrument("Guitar 1");
guitar[1] = new Instrument("Guitar 2");
guitar[2] = new Instrument("Guitar 3");
guitar[3] = new Instrument("Guitar 4");
guitar[4] = new Instrument("Guitar 5");
guitar[5] = new Instrument("Guitar 6");

[code]...

View Replies View Related

Swing/AWT/SWT :: How To Move A Object And Make Object Shot Laser

Mar 27, 2015

can a keyevent in java make the space ship and the laser too ?

View Replies View Related

Inheritance Relationship Between Type Of Actual Object And Object Reference?

Apr 15, 2014

For example I create an object like this:

BankAccount b = new SavingsAccount();

Now lets say that I want to access a method 'addInterest()' that is in the 'SavingsAccount' class I would have to do: '((SavingsAccount)s).addInterest();'

The question I have is why do I have to cast 'b' to SavingsAccount? Isn't the actual object reference of 'b' already an instance of 'SavingsAccount' class? How does the 'BankAccount' affect the object itself? I'm really confused as to what class is truly getting instantiated and how BankAccount and SavingsAccount are both functioning to make the object 'b'.

View Replies View Related

Type In A Name And It Will Search Through Each Object And Print Back Corresponding Object Info

Nov 19, 2014

I am trying to get this to where I can type in a name and it will search through each object and print back the corresponding object info.

Java Code:

import java.util.Scanner;
public class MyPeople {
public static void main(String[] args) {
Person[] p = new Person[] {
new Person("Chris", 26, "Male", "NJ", "Single"),
new Person("JoAnna", 23, "Female", "NJ", "Single"),
new Person("Dana", 24, "Female", "NJ", "Single"),
new Person("Dan", 25, "Male", "NJ", "Single"),
new Person("Mike", 31, "Male", "NJ", "Married") };

[code]....

View Replies View Related







Copyrights 2005-15 www.BigResource.com, All rights reserved