I am trying to write thist method for my project and on line 10 i get the following error : "Cannot instantiate the type Speaker"
public static ArrayList<Speaker> getAllSpeakers() {
ArrayList<Speaker> speakers = new ArrayList<Speaker>();
try {
File file = new File(Resources.SPEAKERS_TXT);
Scanner fileReader = new Scanner(file, "utf-8");
[code]....
I am try to do an application based in multiples JFrames, each one with its particular responsibilities, and use one JPanel as a menu with buttons that connect one JFrame to another, But this menu is instantiated at run in view (layout made by netbeans) the Main Jframe appears with its internal JPanel, but the instantiated JPanel does not appear or does not show it's buttons. (notice only run method in the second class):
JPanel Menu that will be used in all alone JFrames of application:
public class MenuSuperior extends javax.swing.JPanel {
public MenuSuperior() {
initComponents();
} private void initComponents() {
[Code] .....
I need instantiating 3 instances of the RetailItem
//Instantiate 3 RetailItems
RetailItem jacket = new RetailItem(); ITS TELLING ME: constructor RetailItem in class RetailItem cannot be applied to given types
jacket= jacket.setDescription("Jacket"); <------- ITS TEllING ME: cannot find symbol
jacket = jacket.setUnitsOnHand(12);
jacket = jacket.setPrice(59.95);
[Code] ....
Currently my application is on Tomcat5.0.16.I use struts1.2, jstl 1.1 , jsp-api 2.0.I tried to migrate my application from tomcat5.0 to tomcat 6.0.26.I didn't see any issue in deployment but when i tried to access jsp pages i got this exception.
HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: /pbuilder/login/legacyLogin.jsp(6,4) Failed to load or instantiate TagLibraryValidator class: org.apache.taglibs.standard.tlv.JstlCoreTLV
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:88)
org.apache.jasper.compiler.Parser.processIncludeDirective(Parser.java:297)
[code]....
i found that jstl1.1 jar didn't have the above mentioned class.I replaced jstl1.1 with jstl1.2 jar.i verified that jstl1.2 jar had JstlCoreTLV calss.but even after this replacement of jar i am facing the same issue.
I have a list of uninstanciated class types and I wanted to call a static function from these "Class<? extends PropControl>" (without using reflection) that would create a new corresponding object instance but it appears I cant do that in java so now I want to create a factory that takes a class type as aparameter to create the corresponding object instance but this code dont compile:
Java Code:
public PropControl Create(Class<? extends PropControl> cls)
{
if(cls==HouseControl.class) <---- ERROR
{
here I create a new instance of HouseControl (that inherits PropControl)
}
} mh_sh_highlight_all('java');
I get this error :
incomparable types: Class<CAP#1> and Class<HouseControl>
where CAP#1 is a fresh type-variable:
CAP#1 extends PropControl from capture of ? extends PropControl
how do I achieve this ?
I need to create a new text file and instantiate objects using an array that writes them to a file and working with the array part.
public class NewTextFile
{
private Formatter file;
public void openFile()
{
try
[code]....
I have a quick polymorphism question. I have a parent class and a sub class that extends the parent class. I then declare an array of parent class but instantiate an index to the sub class using polymorphism. Do I have to have all the same methods in the child class that I do in the parent class? Here is an example of what I mean.
public class ParentClass
{
public ParentClass(....){ }
public String doSomething(){ }
}
public class ChildClass extends ParentClass
{
public ChildClass(....)
[Code] ....
Is polymorphism similar to interfaces where the child class needs all the same methods?
Below code I am using to typecast int to char.
char escapeValue = (char)0;
char cha = (char) 10;
escapeValue = (char)(escapeValue * cha); // Here am getting the above error.
I have 38 similar issues in my workspace.
If you have final int i = 1;
short s = 1;
switch(s) {
case i: System.out.println(i);
}
it runs fine. Note that the switch expression is of type short (2 bytes) and the case constant is of type int (4 bytes).My question is: Is the type irrelevant as long as the value is within the boundaries of the type of the switch expression?I have the feeling that this is true since:
byte b = 127;
final int i = 127;
switch(b) {
case i: System.out.println(i);
}
This runs fine again, but if I change the literal assigned to i to 128, which is out of range for type byte, then the compiler complains.Is it true that in the first example the short variable and in the second example the byte variable (the switch expressions) are first implicitly converted to an int and then compared with the case constants?
class Passenger{
String name;
int age;
char gender;
int weight;
public Passenger(){
[Code] ....
This is showing error.....error it gives isthat it cannot change from string type to passenger type......... How to do it??????
Got a problem with generics, which I'm still pretty new at. Here's a program that compiles fine:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
It's useless, but it compiles. If I change Line 14, however, to add a generic type parameter to the ListHolder class, Line 10 no longer compiles:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
I get this error:
Uncompilable source code - incompatible types: java.lang.Object cannot be converted to javax.swing.JComponent
at experiments.Experiments.main(Experiments.java:10)
Apparently, the introduction of the type parameter leaves the compiler thinking that aList is of type Object. I can cast it, like this:
JComponent c = ((ArrayList<JComponent>)holder.aList).iterator().next();
That makes the compiler happy, but why is it necessary? How does adding the (unused) type parameter to the ListHolder class end up making the compiler think the aList member of an instance of ListHolder is of type Object?
I have a String repersentaion of some Object.I want that object convert back into some class type how can I do this?
View Replies View RelatedI'm trying to parse and compare the content of a zip file. However I'm stuck at what SHOULD be a very simple problem, however I can't seem to find a solution. I have done the following:
ZipInputStream zin1 = new ZipInputStream(fin);
ZipEntry ze1 = null;
fin2 = new FileInputStream(fileName2);
ZipInputStream zin2 = new ZipInputStream(fin2);
ZipEntry ze2 = null;
//fin.close();
ze1 = zin1.getNextEntry();
ze2 = zin2.getNextEntry();
Which gives me the first entry of each zipfile as a ZipEntry type object. I have tried getting the path of the file (inside the zip file) and using this to create a File type object. This does not seem to work though I get:
Exception in thread "main" java.io.FileNotFoundException: My DocumentsmetadatacoreProperties.xml (The system cannot find the file specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileReader.<init>(Unknown Source)
And this is because I get a null return from trying to create the File file1 = new File(correctLocation);
I guess I cannot access the file inside a zip file this way. So my question is how can I make a ZipEntry type object into a File type object?
I have a value object class and it has the below member
XMLDocument request = null;
Should I instantiate it in the VO class as
XMLDocument request = new XMLDocument();
or leave it null and let the calling program instantiate it?
What's the proper way to do it for Value Object classes in java ?
The objective of the code is to add new records based on existing records with a partial change to the key. I'm getting "type of the expression must be an array type but it resolved to DstidArray" on dsTidRecTbl[i]
String stMajor = request.getParameter("stMajorVersion");
String stMinor = request.getParameter("stMinorVersion");
String stPatch = request.getParameter("stPatchVersion");
StringBuffer stKeySB = new StringBuffer(stMajor+stMinor+stPatch);
String stKey = new String(stKeySB.toString());
DstidArray dsTidRecTbl = new DstidArray(stKey);
request.setAttribute("dsTidRecTbl", dsTidRecTbl);
[code]....
method passing null to the called function, compiler would take that parmer as what type of paramer???
View Replies View RelatedI don't really know what this means and it is sending an error when I try to run my program I am trying to set the x and y value (Int x and int y) to setVisible false at a specific time in my game but it keeps sending the error that int is not a reference type.
View Replies View RelatedI have a problem with my code with Junit:
"The method infinityNorm(double[) is undefined for the Type Vektor."
This error pops up for both the euclidian norm and the manhattan norm.
Here is the code:
package de.ostfalia.gdp.ss15;
public class Vektor {
public static void main(String[] args) {
double[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9};
System.out.println("Euclidian Norm: " + euclidianNorm(array));
System.out.println("Manhattan Norm: " + manhattanNorm(array));
euclidianNorm(array);
[code]...
What is the problem here?
I am trying to understand Life time of a variable by writing a below program. But unable to compile it as it is throwing some error. Code snippet and error as follows,
// Understanding Lifetime of a variable.
class LifeTime {
public static void main(String args[]) {
int x;
for(x = 0; x <3 ; x++) {
int y = -1; // y is initialized each time block is entered
[Code] .....
Please refer to the print screen attached 'LifeTime.jpeg' to this thread to know more about error.
context.getELContext().getELResolver().getType(context.getELContext(), null, "value")
Here "value" is an attribute name. By this we can get data type of the attribute.
By somehow can we set the type also?
I want to implement a kind of "container" in which to store objects (instances) of different types. Then with an iterator I'd call common methods. This is what I have in mind:
Java Code:
with(Positionables){
translate(2, 0, 4);
} mh_sh_highlight_all('java');
Where translate(x, y, z) is a method common for objects in Positionables which objects are of different types (Sphere, Box etc.).
Now I was thinking Positionables could be a List<Positionable> and Positionable is an abstract class and Sphere and Box extends from it. But I don't know how to propagate the call of translate() to the subclasses.
What are the best approaches for this matter? It would be perfect if I could make it so I could somehow use the "with" construction like in the example above.
For some reason when I try to run the program it gives me an "editor does not contain a main type" launch error.
/*
* A program that plays and scores a round of the game Poker Dice. In this game, five dice are rolled. The player is allowed to select a number of those five dice to re-roll. The dice are re-rolled and then scored as if they were a poker hand. The following hands MUST be scored in this assignment:
* * High card
* * One Pair
* * Two Pair
* * Three of a Kind
* * Full House
* * Four of a Kind
* * Five of a Kind
* For extra credit, you may also implement:
* * Straight
*/
import java.util.Scanner;
public class Project10 {
public static void main(String[] args) {
Scanner inScanner = new Scanner(System.in);
int[] dice = new int[5];
resetDice(dice);
System.out.print("Your current dice: + dice");
[code]....
If I type
long z = 0xDeadCafe;
System.out.print(z);
I get a negative number as a result.
But if I append an L to the hex number:
long z = 0xDeadCafeL;
the resulting number is a positive one.
What the difference is between those two lines:
long z = 0xDeadCafeL;
and
long z = 0xDeadCafe;
(same as above, but without the suffix L).
If I don't append the L, is the msb (most significant bit) somehow still carried over to the resulting long variable and in the latter case, where I append an L, it is not and instead the value is filled up with 32 leading zeros (4 Byte difference between int and long)?
When I write a statement such as:
myType x;
This means that x is a reference to objects of type, "myType" and no memory has been set aside for an instance of this object. I think it's true that x also has the starting memory address of this object.
What I feel uncertain about is if x is telling the JVM(?) where it can find the starting address of this object, why do we care about the type that x is?
i.e., if we assign x to an object totally unrelated to this type then the compiler would complain - correct? If so, how come, since all x is doing is telling the JVM(?) where to find your object (via the address it contains).
I suppose all, hy a reference has a type associated with it if all the reference does is point you to the object?
I'm trying to run a simple code which is to just print out "Hello World", but whenever I run it, a message appears that reads: "Select a way to run Project_1(Which is the Java Project)"
The selections for it are: Java Applet and Java Application.Whenever I click Java Applet it reads: Selection does not contain an applet.When I click Java Application: Selection does not contain a main type.Here is the code which I believe is correct:
package packag_1;
public class Num_1 {
public static void main(String args){
System.out.println("Hello World");
}
}
I recently switched some of code around to restructure how some things were working but now when I run the program I am getting a NullPointerException in multiple areas. I suspect it may have something to do with a constructor. I am very new to "object" - ish based programming.
I figured I should give a little background on the program, this program is reading from a text file of names and decade numbers(for each name) and storing each line into an object array. From there, there are menus and based on the users decision they can type a name and get a histogram, compare names with histograms, ect. Below this main method, I have provided the area where I have gotten the null pointer exception.
Here is the main method for the Client "nameApp"
Also excuse the formatting and curly braces for now!
public class NameApp{
private static boolean validInput;
private static boolean done = false;
private static boolean validDecade;
private static boolean validName;
[Code] ....
And here is the method in the same Client that is getting the null pointer exception:
The pointer exception is on line 6 which is:
if (nameInput.equalsIgnoreCase(list[i].getName())){
private static int checkListArray(String nameInput, Name[] list){
int nameLocation = -1;
int listLength = list.length;
[Code] ....