Why I cannot use 2 public classes like below?
public class Hello {
public static void main(String[] args){
Welcomer welcomer=new Welcomer();
welcomer.sayHello();
[Code] ....
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
The public type Welcomer must be defined in its own file
at Welcomer.<init>(Hello.java:9)
at Hello.main(Hello.java:5)
I have a small issue understanding the following error message that Eclipse returns when i try to run the following code:
class Film {
String tytul;
String rodzaj;
int ocena;
void odtworz() {
System.out.println("Odtwarzamy film.");
[Code] .....
The message itself reads: "Exception in thread "main" java.lang.Error: Unresolved compilation problem:
at FilmTester.main(Film.java:13)"
and the following on the line where the problem arises:
What gives? I'm positive i'm missing something obvious but i can figure it out why
I am having a little trouble with a part of my Java assignment that needs to have linked lists in it.
I need to write a public method that takes an array of type object to load strings into a linked list.
I've got a problem in Eclipse. The below code is a part of my program, used for (re)starting a new game. The 'public static int' statement gives the error 'This method must return a result of type int'..
public static int playAgain(){
boolean validInput = false;
do {
System.out.println("Would you like to play a game? Please answer 'yes' or 'no'.");
String playAgain = input.next();
[Code] ....
The compiler won't let me declare more than one class as "public". Am i correct in understanding that this is a java restriction ? This means i need to create a new file, for each public class that i want in a package ? The rest of the classes without access modifier will all be package-private. (Q has been asked before probably, but my search could not be narrowed).
View Replies View RelatedI have a question about the following snippet concerning the steps the javac compiler follows to compile a program:
[...]at first, searching a class within a package is discussed if the latter doesn't contain a full package name[...]
It is a compile-time error if more than one class is found. (Classes must be unique, so the order of the import statements doesn't matter.)
The compiler goes one step further. It looks at the source files to see if the source is newer than the class file. If so, the source file is recompiled automatically. Recall that you can import only public classes from other packages. A source file can only contain one public class, and the names of the file and the public class must match. Therefore, the compiler can easily locate source files for public classes.
However, you can import nonpublic classes from the current package. These classes may be defined in source files with different names. If you import a class from the current package, the compiler searches all source files of the current package to see which one defines the class. I don't quite understand the red fragment. I wondered if the word "import" nonpublic classes from the current package weren't a synonym for the word "use", since why would we want to import a class from the same package when compiler searches the current package automatically anyway?
However I wanted to test nonpublic classes that are contained in source file which name doesn't match the class name:
NonpublicClass.java:
Java Code:
package com.work.company;
class NonpublicClass
{
public void description() {
System.out.println("Working!");
}
} mh_sh_highlight_all('java');
[Code] ....
Everything's fine when the source file names are the same as above. However, when I change NonpublicClass.java to a different name, there's an error "cannot find symbol" in:
Java Code: NonpublicClass v = new NonpublicClass(); mh_sh_highlight_all('java');
I noticed that the class file for NonpublicClass isn't even generated so that's probably the cause. If I change to the directory of the package the NonpublicClass is contained in and compile it directly, i.e. issue for example:
Java Code: javac NonpublicClass_different_name.java mh_sh_highlight_all('java');
Then a proper class file is generated with the class name, that is NonpublicClass.class, and afterwards I can compile the main program in Start.java.
So the question is what am I missing regarding the cited quote that reads:
If you import a class from the current package, the compiler searches all source files of the current package to see which one defines the class.
? Because adding such an import to CompanyClass.java:
import com.work.company.NonpublicClass;
didn't work either...
I'm using a PrimeFaces UploadedFile xhtml page to select a csv file to read and write using a managed bean (SuperCSVParser.java). The file is read and written to an entity class which then persists the data to a database. The application works fine if I specify a file path on the physical server and select a csv file on that file path. But for the production version I want the user to select ANY file name from ANY directory on their local system.
I know about the FacesContext methods and I've looked at some methods from the java.io File class. Most of these methods are about getting the path from the server, where I want to 'pass' the path String from the client machine to allow the uploaded file to go through. When I try with the below code I get:
java.io.FileNotFoundException: data.csv (The system cannot find the file specified)
I'd like to know what I'm doing as I prefer not to explicitly declare a path in the final app. I'm almost sure that's possible.
<h:form enctype="multipart/form-data">
<p:fileUpload value="#{SuperCsvParser.file}"
mode="simple"
auto="true"
[Code].....
I'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?
Basically I'm trying to code this program but I keep getting error can't be applied to given types. I know it has to do with my method trying to be called by an array, but I'm just kinda lost.
Write a program that prompts the user to input cash amounts and use a method to calculate the average amount for a week given 7 inputs of daily cash intake amounts for a cash register. Use an array to store the values. Recall that average is the sum of the values divided by the number of values. The method should take argument(s) of type double and return average weekly cash amount as a double.
Make sure you test your program using the test data given below and calls the averageCash() method defined above passing in the values. Verify that the input values are greater than or equal to 0. Negative numbers are not allowed. Output the values used and the averageCash value.
import java.util.*;
public class ArrayHandout {
public static void main(String args[]) {
int[] a=new int[6];
Scanner sc=new Scanner(System.in);
[Code] ....
I am getting the error message as Exception in thread "main" java.lang.Error: Unresolved compilation problems: NewExcel cannot be resolved to a type for the line NewExcel test = new NewExcel(); in the below code to read the columns from an excelsheet "test.xls". Why I am getting the error message :-
import java.io.File;
import java.io.IOException;
import jxl.Cell;
import jxl.Sheet;
import jxl.Workbook;
import jxl.read.biff.BiffException;
public class ReadExcel
[Code] .....
I am currently working on modules of a java program but am having issues with this module . it gives this error code"syntax error on token '?', invalid primitive type".
This is my code:
import java.awt.*;
import java.awt.event.*;
import java.io.PrintStream;
import java.rmi.Naming;
import java.util.StringTokenizer;
[Code] .....
Getting the following error at line 13.
Multiple markers at this line - void is an invalid type for the variable loadDictionaryFromFile - Syntax error on token ")", ; expected - Syntax error on token "(", ; expected
Line 13 starts public void load....
Code:
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class PirateTranslator
{
public static void main(String[] args)
[Code] .....
I am new to Java and trying to learn it.I wrote the following program but while creating the method nav i am getting errors.
Error:- void is an invalid type for the variable nav
import org.openqa.selenium.*;
import org.openqa.selenium.firefox.FirefoxDriver;
import java.util.*;
public class YahooHomepage {
private static WebDriver driver;
[Code] .....
Here is a code and error .....
View Replies View RelatedI have a simple doubt
float k = 0;
k+=0.2;
k=k+0.2; // here compilation error
compliation error Type mismatch: cannot convert from double to float
My question is why not a complilation error at k+=0.2;
I have a code in which I am reading input from System.in and Destination is some where else
Here is my code
File file=new File("D:/output.txt");
OutputStream os=new java.io.FileOutputStream(file);
Scanner scanner=new Scanner(System.in);
System.out.println("Enter Data to write on File");
String text=scanner.nextLine();
int c=Integer.parseInt(text);
int a;
while((a=c.read())!=-1)
os.write(a);
System.out.println("File Written is Successful");
In the line while((a=c.read())!=-1)
a compile time error is shown "cannot invoke read on primitive data type int"
Where I am going wrong?
This code is directly from Swing: I'm using Eclipse and keep getting an error on line 10 saying :
"The type JTextField must implement the inherited abstract method ActionListener.actionPerformed(ActionEvent)."
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
[Code] ......
String contentType = fi.getContentType(); gives text/plain when my file is.txt file and gives image/jpeg when my file is .jpeg file but when my file is .jar or .docx it will return application/octet-stream and application/vnd.openxmlformats-officedocument.wordprocessingml.document respictively so what to do to get exact mime type.
View Replies View RelatedIs there a way of detecting the file's type (whether it is a pdf, jpg, png,or anything else) by reading the content of the file. We could read the extension of file to determine it's type, but then extensions can be forged too. So I would like to know if the content inside a file is of a particular type or not. I'm not sure about this, but I have heard somewhere about each having having a specific kind of header which determines its type. So is it possible to read that header and determine it using a program?
View Replies View RelatedI'm a independent IT contractor. On 2 systems this week I've experienced an issue when attempting to download JAVA the file is of an unknown type in IE. See attached. Alternative browsers on the same machine function properly.
View Replies View RelatedI want to create a program where I need to create an object of list type such as text file will contain nos like 1,2,3,4,5 and write into text file and delete the in FIFO order i.e 1,2,3,4,5...how i can achieve to write a program? I tried bt everytime got concurrent modification exception or Array out of bound exception.
View Replies View Relatedpublic class InputFileData {
/**
* @param inputFile a file giving the data for an electronic
* equipment supplier’s product range
* @return an array of product details
* @throws IOException
*/
public static Product [] readProductDataFile(File inputFile)
throws IOException{
// YOUR CODE HERE
}
This code is meant to be used to read a text file and store the data in an array of type Product[]. I know how to read in a text file and have it sort it into an array, but I've never seen code laid out in this fashion before (specifically "public static Product[]", and I'm unsure how to work with "(File inputfile)". I've looked all over the place but can't find any examples of anything like this.
Also, the code given cannot be changed, as it's that code I have to work with.
I still don't understand how to use it as a whole. For example, do I read the file in the main and have this method read that in and output to the Product class? Do I read the file in this method? I can't work out how to make this work when I have to use this method.
If I specify the directory in file type or path string type how can I get a list of files that are file type .yml in that folder, so I can loop through and do something with each single file.yml in that specified directory.
View Replies View RelatedThis issue is regarding response from the servlet
I have written a code to download .csv file with records from DB.
To download records i am uploading a .CSV file containing telephone number.
After downloading the .CSV file page is not getting refreshed.
Below is the code snippet i am using,where i am setting response content type as test/csv.
ServletOutputStream op = resp.getOutputStream();
// Set content type of output
resp.setContentType("text/csv");
resp.setHeader("Content-Disposition", "attachment; filename="test"");
op.flush();
op.close();
How that page will get refreshed after csv file download or after response.
I am simulating a game. This involves creating two Player objects(either HumanPlayer or ComputerPlayer), a TheBoard object, a TheGame object and a TheGameManager object. In the TheGameManager, i am trying to get it so that i can save the two Player objects, the TheBoard object and the TheGame object in current use at some point in the game and then load them later at some point. However, after debugged, i have found that it doesnt like the writeObject() method and skips and sends an exception up.
My TheGameManager class has the following fields:
public class TheGameManager implements GameManager {
private Player player1;
private Player player2;
private TheBoard currentBoard;
private TheGame currentGame;
//private String[] args;
private int iterations = 1;
[Code] .....
I have Spring/CXF project in RAD. I have the following problem message:The servlet mapping "XXX" refers to a servlet that is not defined.
<servlet>
<servlet-name>XXX</servlet-name>
<display-name>XXX</display-name>
<servlet-class>org.apache.cxf.transport.servlet.CXFServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>XXX</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
However, The servlet was defined in the web.xml file.I searched the internet and tried a few things but to no avail.