How To Create File References
Sep 7, 2014Is 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?
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Generics Wildcard Array Of References?
Jul 27, 2014An 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.
How To Do A Deep Copy Of Objects That Contain References
Mar 21, 2014how 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].....
Launcher References Object Variable
May 22, 2015So 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);
Object Pool Using Phantom References
Apr 19, 2014I 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] .....
Would Switching References Change Their Graphical Position?
Jan 19, 2014So 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 RelatedModify 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]....
Reading Text File Into Object Array And Create Random Access File
Dec 9, 2014I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data. Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
[Code]...
these continue for about 40-50 entries, they are not seperated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name seperated with spaces, then price after a comma, then quanity after the second comma.....
Create New File / Ask User To Write In It And Save Final Print Content Of File
Mar 15, 20141. creates a file.
2. ask user to write into that file
3. save the file
4. print content of file.
Is my current exercise, so far i have gotten the code to create a file. What should i use to ask user to write into that file and save?
package assignment7;
import java.io.*;
public class Exercise2
{
public static void main ( String [ ] args ) {
String filePath="newfile.txt";
File newFile = new File ( filePath ) ;
[Code] .....
Create New File / Ask User To Write In It / Save Finally Print Content Of File
Mar 17, 20141. creates a file.
2. ask user to write into that file
3. save the file
4. print content of file.
is my current exercise.so far i have gotten the code to create a file, and ask the user to input their age.what should i use to save what the user writes into the file?
Java Code:
package assignment7;
import java.io.*;
import java.util.*;
public class Exercise2
{
public static void main ( String [ ] args ) throws IOException
{
Scanner scan = new Scanner(System.in);
[code]....
Creating A System That Will Ask User To Create A File That Will Store To Text File
Mar 9, 2015I am new to java and I am creating a system that will ask the user to create a file that will store to a text file, Once the user created the file I have a class that will let the user input the subject name that has been created, However, I keep on getting this java.util.nosuchelementexception.Here's my code:
public void display_by_name()
{
String id, name,total;
String key[]=new String[30];
String value[]=new String[30];
int i=0;
[code]....
Read Input File And Create Output With Anagram For Words In File
Sep 24, 2014Well my code is supposed to ask for an input file and then (ex: input.txt), read the input file and create an output.txt file with the anagram for the words in the file. Also it should be displayed on the screen. However my code doesn't display the anagram on screen or the output file!
Heres is the code:
import java.io.*;
import java.lang.*;
import java.util.*;
/* This program will read a file given by the user, read the words within the file and determine anagrams of the given words. If the file that the user inputs is empty, then the program will output "The input file is empty."
* The program will read the file line by line, counting the total number of words read. If there are more than 50 words, "There are more than 50 words."
* will be printed, and the program will terminate. After each line is read, the words in the line will be separated,punctuation characters will be removed, and upper case characters will be switched to lower case.
* If any word is larger than 12 characters, that word will not be considered in the total amount of words in the file and it will not be sorted.
* After each word is read, the letters will be sorted and stored into an array containing each
* word's 'signature'. After all the words have been read, words will be printed to the output file on the same line based upon their signature.
*/
public class Anagram {
//Creating constants for maximum words in file and maximum chars in word
public static final int MAX_CHARS = 12;
public static final int MAX_WORDS = 50;
[Code] ....
How To Create Jar File Of Program With Text File
Jan 29, 2015i have made one desktop application with swing and i have uses one textfile (File) in it. i want to handover to another friend to use it . How to create jar file of that program with that text file so that my friend use it without any issue . I have made it in NetBeans
View Replies View RelatedPractical Use Of Multiple Object References Pointing To Same Object
Dec 27, 2014I 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]....
How To Create GIF File
Feb 2, 2015is it possible to make a .gif file with jave?
if it is, how is it done?
do i just create a bufferedGif object, or somemthing like that?
Can't Create A New File
Jul 17, 2014code:
import java.io.*;
class FileWrite
{
public static void main(String args[])
[Code]....
error :
d:jpro>javac FileWrite.java
FileWrite.java:11: error: constructor File in class File cannot be applied to given types;
File f=new File(filename);
^
[Code].....
Create Jar File
Nov 9, 2014create a jar file.Currently I have next files in my directory:
Manifest.txt:
-------------
Manifest-Version: 1.0
Created-By: 1.7.0_60-ea (Oracle Corporation)
Main-Class: connectURL
connectURL.class
------------------
it compiled fine, can be executed as:
java connectURL
it does not have 'Package' specified
sqljdbc4.jar
-----------
This is jdbc 4 jar file which is used by connectURL.java to make db. connection.
I am running:
C:j>jar cvfm connectURL.jar Manifest.txt *.class sqljdbc4.jar
added manifest
adding: connectURL.class(in = 2427) (out= 1358)(deflated 44%)
adding: sqljdbc4.jar(in = 584207) (out= 549364)(deflated 5%)
Then trying to execute and get error message
C:j>java -jar connectURL E520 1433
Error: Unable to access jarfile connectURL
How To Create A JAR File
Jan 30, 2014how to create a JAR File I have been watching you tube and it seems like the manifest needs to be remade. I go to the CMD and find my project folder class. I think I need to use do the same for all the classes correct. Well I type jar -cf TictacToeGUIGame.jar *java then I get no such directory. I can see the it worked thought. So do i do this to all my classes and then I will have my JAR program?
View Replies View RelatedCan't Create Jar File
Apr 2, 2014text file:
Codebase: myserver.com
Permissions: sandbox
Application-Name: Dynamic Tree Demo
error message from command line:
C:UsersxxxxDesktopCOMP268applet_ComponentArch_DynamicTreeDemoapplet_Comp
onentArch_DynamicTreeDemouildclasses>jar -cvfm DynamicTreeDemo.jar mymanifest
.txt appletComponentArch
java.io.IOException: invalid header field name: ?≫?Codebase
at java.util.jar.Attributes.read(Attributes.java:433)
at java.util.jar.Manifest.read(Manifest.java:199)
at java.util.jar.Manifest.<init>(Manifest.java:69)
at sun.tools.jar.Main.run(Main.java:172)
at sun.tools.jar.Main.main(Main.java:1177)
[/code]
encoding in UTF-8 and have newline at end
How To Create A Text File
May 10, 2014File f=new File("c:/FilePractice/text.txt");
f.mkdirs();
and it creates only the folder text.txt.i am trying to create a blank txt file int this folder?what is the easiest way to do it? i try this one also:
[CODE]
PrintWriter writer = new PrintWriter("test.txt");
writer.close();
[CODE]
and its work but the test.txt file created in sort of default folder in my project folder.how can i make it in a folder that i want?
Create A New Xml File With DOM Parser
May 29, 2014I try to create a new xml file with DOM parser and i get this error in line 73.
Java Code: package RunMABS;
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
[code]....
How To Create PDF File While Working In Java
Feb 22, 2013how to create pdf file while working in java.
View Replies View RelatedEJB / EE :: Create EAR File From Myeclipse Workspace
Jun 12, 2014Actually I use MyEclise to develop and deploy a enterprise project(EAR file). I use Java Build Path to add some other projects and link sources, and added several jar files (as external jar and user library) to my project. (I used J2EE technology and there are some default jar of course )
By myeclise deploying manager I deployed my project on weblogic base_domain and then by weblogic console I deploy it on weblogic. All is set and there is no problem in all steps.
Now I wanna to create EAR file manually, first I created WAR file which included some jsf files and web-inf directory contains classes, lib directories and some important file like web.xml , facec-config.xml and etc.
In classes folder I have .class files which build correctly from .java files, and on lib directory**I copied all jar file from web-inf/lib directory** which created automatically by myeclipse deploying manager on weblogic base domain folder.
I added this War file into EAR file along APP-INF directory which contains all jar files from APP-INF/lib directory on weblogic base domain folder and META-INF directory what contains application.xml file.
When I deploy this ear file on weblogic there is so many error and problems. What is the correct way to create that EAR file.
Create A New Line On TXT File Between 2 Lines
Feb 6, 2015Lets say this txt file contains 2 lines.
---------
hello
bye
---------
What would i have to do to insert a a piece of text in between hello and bye? I would like for the it to search for "hello", then add a line after it so it would look like :
-------
hello
newtext
bye
-------
I have these 2 methods that work as intended, but i just cannot seem to do what i've stated above.
Java Code: /**
* @param location
* Location of the .txt file.
* @param text
* The String to search for in the .txt file.
[Code] ....
How To Create Excel File In Java
Mar 30, 2014Attached Images
File Type : 10.jpg (21.9 KB)
Using JarOutputStream To Create A Runnable Jar File
Apr 26, 2014How does one use java.util.jar.JarOutputStream to create a jar file on button press? This new jar file, I want to make it runnable so it performs a specific action on run..
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