Why Does Compiler / IDE Force To Use Static In Code
Oct 24, 2014
I'm a beginner fiddling around classes in Java. I noticed on this particular code, Eclipse will give me an error and suggest I put the static keyword in front of the variable.
public class test {
//the following line is where Eclipse puts the static keyword
static FileAccess hello = new FileAccess("D:" + '\', ".mp3");
public static void main(String[] args) {
for (int i = 0; i < hello.getTotalNumberOfFiles(); i++) {
[Code] .....
The FileAccess class is just a class I made while trying to retrieve filenames from my hard drive.
As far as I can tell, it works correctly after I put the static keyword there. I just want to know why it is required in this particular code, considering it didn't need to do that when I made a simpler class while I was getting my feet wet at creating classes in Java.
I am using a static method to convert a string to an Integer object. Next using a instance method to convert Integer object to an int.
Compiler is giving me two "cannot find symbol" errors:
One pointing to the dot operator between "Integer.valueOf(s)"
The other pointing to the dot operator between "obj.intValue()"
I have latest JDK installed: jdk-7u51-windows-x64.exe
Looks like JCL installed correctly with rt.jar file located in "lib" directory under "Program Files"
Following is source code:
Java Code:
public class StringToInt { public static void main (String args []) { String s = "125"; Integer obj = Integer.valueOf(s); int i = obj.intValue(); i += 10; System.out.println(i); } } mh_sh_highlight_all('java');
I need to do a simulation on the assembly code level by writing a mini-compiler for each ISA, i.e., 4, 3, 2-Address Architecture, Accumulator Architecture, Stack Architecture, and Load-Store Architecture.The input to the simulator is a segment of C program:The basic sample segments of C code are:
In the header I have a combo list. At each change in value in the combo list I have an Ajax request that updates the data in the Body. So far everything is working properly. Now the home screen's structure should be change when the value of combo list change. To do this I have :
- 1 ManagedBean HomeBean that manage the home - 1 ManagedBean HeaderBean that manage the header - 2 object HomeScreen1.java and HomeScreen2.java that allows me to valued data from each screen - 2 services HomeScreen1Loader.java and HomeScreen2Loader.java that manage loading of each type of screen - 1 template home.xhtml - 2 fichier home1.xhtml et home2.xhtml
When I log in to the application, I get the good page corresponding (Element type 1 => home page 1). But when I select a type 2 item, the actionListener methode is execute, ManagedBean's data was updated (for type 2 screen) , but the page does not updated. What do you do ?
Whether it is possible to force the installation of JRE when trying to open JNLP file. It is quite often case when users try to run JWS application without JRE installed. The best option would be to force the installation or at least display some message with instructions. Perhaps there are different ways to handle this problem.
In other words in a table view with several editable columns, when a new row is added this row does not contain any column cells yet. Cells are added on demand once a column gains focus and starts editing. Is this the case? Is there any way to force the row to construct all cells eagerly?
I noticed that when building a UI programmatically in several steps the width/height of the Pane I use for layout is -1/-1. I read that this is the case until the actual rendering happens. Is there a way to force that earlier? Suppose I wanted to size other UI components (which are not visible initially) according to the size of another pane. How do I do that? Binding the properties does not do the job in the case that those components are not necessarily visible at the same time. Is there a trick to achieve that?
We've implemented the Whitelist and there's an application I need to use the Force attribute with, however, I'm unable to get this to work. As I read it, this code says use Java 1.6_24 for Example.com and any other applications are blocked from running. There are three versions of Java installed - 1.6_24, 1.7_65 & 1.8_25. The Java console shows 1.8_25 being called.
Here's the ruleset.
<ruleset version="1.1+"> <rule> <id location=https://example.com /> <action permission="run" version="1.6_24" force="true" /> </rule> <rule> <id /> <action permission="block"> <message> This application is blocked due to Java restrictions, please contact the Service Desk for assistance.</message> </action> </rule></ruleset>
I also tried
<action force="true" permission="run" version="1.6.0_24" /> and also <action force="true" version="1.6.0_24" permission="run" />.
The Java console is still showing version 1.8.0_25.
I use this code in Restlet Representation. I try to get the value from the Request API. But I am facing the problem as "Cannot make a static reference to the non-static method getQuery() from the type Resource".
From what i understand static methods should be called without creating an instance of the same class . If so why would they return an instance of the same class like in the following : public static Location locateLargest(double[][] a) , the Location class being the same class where the method is defined . I don't understand this , does it mean that every field and every method in the class must be static ? Meaning that you cannot have instances of the class because everything is static . Or it's just a mistake and the class Location cannot have a static method: public static Location locateLargest(double[][] a) ?
I can't figure out what this error message "Cannot make a static reference to the non-static method getEndUserCharge(long, long, long, long) from the type UpdateUserWS" actually means.
The error is coming from:
public void updateDetailsPackage() { some unrelated code long zero=0; double endUserCharge=0; endUserCharge = UpdateUserWS.getEndUserCharge(long zero, long zero, long zero, long zero); <-------- error is here
I am trying to call an actionListener which is shown below in my PSVM :
class testMenuItemListener implements ActionListener { public void actionPerformed(ActionEvent arg0) { getContentPane().removeAll(); createPanel(); getContentPane().add(panel1); //Adding to content pane, not to Frame repaint(); printAll(getGraphics()); //Extort print all content
[Code] .....
I get the following error :
Frame.java:409: error: non-static variable this cannot be referenced from a static context menuItem1.addActionListener(new testMenuItemListener());
I am trying to add a field (called special) to a hibernate table. I am copying existing code (related to the NAME field) so I don't have to figure this out from scratch. I am getting the error
"[ERROR] C:VOXvoxware-1.1.13voxwarevoxware-implsrcmainjavacomvoxwareimplflowVoxFlowConfiguration.java:[213,38] error: non-static variable special cannot be referenced from a static context".
Line 213 is in public void mergeFrom, the actual line is "special = VoxFlowConfiguration.special;" I don't understand why Java thinks special is a "non-static" variable but it doesn't have a problem with the other variables (such as name, orderShow)
I'm working on a banking program that is supposed to use 3 classes (Account-base class, CheckingAccount, and SavingsAccount) and several methods to display the banking information (ID, balance after a withdrawal and deposit, and the annual interest rate). This should be a pretty simple program, but I'm getting hung up on one portion of it. I'm getting some compiler errors, all of which deal with non-static variables being called from a static context (I'll also post these errors following the code). Up until the middle of last week, we just declared everything as static, but that's changed and I'm having trouble figuring out when to and when not to use static when declaring my methods, hence the compiler errors.
import java.util.Date; public class Account { private int id = 0; private double balance = 0; private double annualInterestRate = 0; private Date dateCreated = new Date();
[Code] ....
Here are the compiler errors I am receiving:
Compilation completed. The following files were not compiled: 6 errors found: File: C:UsersHiTechRedneckDesktopSummer II 2014Computer Programming PrincipleProgram 5CheckingAccount.java [line: 7] Error: non-static method getId() cannot be referenced from a static context
I am trying to call an actionListener which is shown below in my PSVM :
class testMenuItemListener implements ActionListener { public void actionPerformed(ActionEvent arg0) { getContentPane().removeAll(); createPanel(); getContentPane().add(panel1); //Adding to content pane, not to Frame repaint();
[Code] .....
I get the following error :
Frame.java:409: error: non-static variable this cannot be referenced from a static context menuItem1.addActionListener(new testMenuItemListener());
I am writing the following program in Java SE 7. It throwing "Cannot make a static reference to the non-static type String" . However if I write parameterised String inside main method as java.lang.String[] args, it compiles fine.
class MainClass<String> { <T> MainClass(T t) { System.out.println(t.getClass().getName()); } public static void main(String[] args) { System.out.println("asdasd"); new MainClass<>(""); } }
I mean following programs compile fine in Java SE 7 :
class MainClass<String> { <T> MainClass(T t) { System.out.println(t.getClass().getName()); } public static void main(java.lang.String[] args) { System.out.println("asdasd"); new MainClass<>(""); } }
If i try to make it public void than it say can't call non-static methods inside static(main).if i try to put it into new class and then call it after i fail input it goes into infinite loop.
The error said : Non Static Variable TAShaReport Cannot referenced from a static context
I just want to put the output in the TextArea
Here is the code :
public static String DeduplicateFiles(String myFolderLocation) { try { HashSet<String> newset = new HashSet<>(); File folder = new File(myFolderLocation); //Directory where the files are located File[] listOfFiles = folder.listFiles();
I had a TestColor class which contained methods to change hue, saturation, brightness, red, green, blue of TestColor's instances but also had static methods which take in an additional parameter for an instance of TestColor and returns the affected instance of TestColor. Now instead of having one method for every possible color effect to be applied to an image, how can I have one method that takes in an Image parameter, a static or non-static method reference from TestColor parameter and lastly an intensnity value parameter. This is so that I can make an affectedImage object instance inside the method and a Graphics2D object for drawing to each pixel of the new image, now I have one for loop and one nested for loop for the x and y pixels of width and height of the old image and inside the nested for loop I'd create a TestColor by calling getRGB on the image's pixel. Then I would apply the static or non-static method reference somehow to change the color with the intensnity value and after applying it draw to the new Image with Graphics2D. How to would I parametize a method reference and be able to use it in such way?
