Netbeans And Non-static Variables
Feb 11, 2014
I'm doing in this small piece of code -
JavaApplication3.java
package javaapplication3;
public class JavaApplication3 {
public class robot {
int xlocation;
int ylocation;
String name;
static int ccount = 0;
[Code] .....
When I'm trying to compile it with netbeans i get these errors and i just can't figure why is that!
C:UsersuserDocumentsNetBeansProjectsJavaApplication3srcjavaapplication3JavaApplication3.java:16: error: Illegal static declaration in inner class JavaApplication3.robot
static int ccount = 0;
modifier 'static' is only allowed in constant variable declarations
C:UsersuserDocumentsNetBeansProjectsJavaApplication3srcjavaapplication3JavaApplication3.java:30: error: non-static variable this cannot be referenced from a static context
robot firstrobot = new robot(34,51,"yossi");
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Oct 28, 2014
Why I can create an Instance of a class that contains non static variables within the static main method ?
This program runs fine
import java.util.*;
public class Test{
public int j;
public static void main(String[] args) {
Test test1=new Test();
System.out.println(test1.j);
[Code] .....
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Aug 6, 2014
Can we use static variables or static objects in servlets ?? I want to restrict same user to enter into the application from different system when the user is already working, he needs to get a message saying "User is already in use ".
I have created static SET object in LoginServlet and inside doget() I checked if SET contains user ,if yes display him above message otherwise add the user in SET object and forward it to next page . Later while logging out user is removed from SET .
Can I follow any other approach other than using static object SET in servlets??
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Oct 27, 2014
why using the get method(c.get(c.HOUR_OF_DAY)); gives me the correct hour(currently 19) but directly accesing c.HOUR_OF_DAY returns 11 ? It shows In the documentation that HOUR_OF_DAY is public.
import java.util.*;
public class calendar2 {
public static void main(String[] args) {
new calendar2().timer();
}
private void timer() {
Calendar c=Calendar.getInstance();
//c.clear();
System.out.println(c.get(c.HOUR_OF_DAY));
System.out.println(c.HOUR_OF_DAY);
}
}
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Oct 22, 2014
Say I have a class called ClassA which I want to hold my data. Now inside ClassA want to hold instances of a class lets call ClassB. So far we are here.
import blah.B
public class A {
private B myB;
(Getters setters etc)
public String getBString() {
B.getString();
}
}
However I want to have multiple extensions of ClassB which have UNIQUE static variables.
public class B-1 extends B {
private static String mString;
private static int mInt;
}
The problem I have run into is I can't have subclasses with their own static variables. I need the A class to hold any type of B class. How can I manage this?meant
public String getBString{
return B.getString();
}
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Feb 20, 2014
I'm new to Java and I'm trying to create a spanning tree in the desired order with 4 nodes (0,1,2,3). I've got the following code:
import java.util.ArrayList;
public class A {
public static boolean any(ArrayList<Integer> input) //To check for if any element in the ArrayList == 1
{
boolean answer = false;
for(int i=0;i<input.size();i++) {
if(input.get(i)==1)
[Code] ....
What happens is that the input parameter adj and hence the original adjmat inside main gets changed everytime I enter the method "connected", and I don't want this to happen. I understand that this is due to the main method being static and hence adjmat becomes static as well, but how do I change the code such that adjmat only gets modified after coming out of the connected function, and not while inside it?
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Jan 22, 2015
Are the static variables in servlet thread-safe?
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Feb 19, 2011
I thought static methods could never use instance variables, because they wouldn't know which instance to look at.
From Head First Java, p. 284: "A static method is not associated with a particular instance - only the class - so it cannot access any instance variable values of its class. It wouldn't know which instance's values to use."
Now I was answering some mock exam questions from Cameron McKenzie's SCJA book, and I don't understand one of the options. On page 205, the last question has an option that says: "Instance variables ... are not visible in static methods, unless passed in as arguments." This option is supposed to be correct. Now... how does that work?
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Sep 24, 2014
a code to search for static variables that look like username or password.i want to be able to search through a source code for such variables.
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Mar 26, 2015
This is my code inside the method:
@Post
public static String getDetails(Representation entity) throws Exception {
String customerId = getQuery().getValues("cus_id");
}
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".
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Jun 27, 2014
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) ?
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Apr 26, 2015
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
[Code] ....
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May 26, 2015
Alright, I have two classes, this one
public class Player {
private String player;
public String getPlayer() {
return player;
}
private int strength;
private int defense;
[Code] .....
However, it says that under Player.getPlayer() that it 'Cannot make a static reference to the non-static method'.
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Mar 15, 2015
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());
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Mar 3, 2015
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)
package com.voxware.impl.flow;
import com.voxware.asset.LiabilityType;
import com.voxware.flow.FlowConfiguration;
import com.voxware.flow.OrderFlow;
import com.voxware.flow.Step;
import com.voxware.i18n.LanguageCodes;
import com.voxware.impl.i18n.UTF8Control;
import com.voxware.impl.persistence.BaseEntity;
import com.voxware.impl.portal.VoxPortal;
[code]....
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Jul 27, 2014
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
[Code] .....
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Mar 14, 2015
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());
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Apr 27, 2014
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<>("");
}
}
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Aug 19, 2014
i am trying to make something, and i want to request input from user and it shoud look like this
1. xxx -> press 1 to choose this
2. xxx -> press 2 to choose this
So if they enter 3 or string or whatever i want to restart method and show again
1. xxx -> press 1 to choose this
2. xxx -> press 2 to choose this
So here is method that i am trying to restart
public static void askUser(){
System.out.println("xxx");
System.out.println("1. xxx");
System.out.println("2. xxx");
System.out.println("3. xxx");
[code]....
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.
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Sep 28, 2014
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();
[Code] .....
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Nov 18, 2014
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?
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Nov 18, 2014
This is a someway special question, because I am using jmonkeyEngine.
But the topic is simple:
I have 2 classes:
public class Spielbrett extends SimpleApplication {
public static void main(String[] args) {
Spielbrett app = new Spielbrett();
app.start();
}
@Override
public void simpleInitApp() {
[Code]...
as the main class and a second class for the chips:
public class Spielstein {
public Spatial stone;
public int player;
public int team;
private AssetManager assetManager = Spielstein.getAM(); //THIS IS THE PROBLEM
public Spielstein(int t_player, int t_team){
[Code]...
My problem is: I can't access getAM() from the first in the second class. If you know why I would be glad for an answer.
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Apr 3, 2014
This is the overall code:
public class Bank {
/**
* Customer class.
*/
public class Customer {
private String firstName, lastName, street, city, state, zip;
[Code] .....
The error occurs when I attempt to create the new object Account within the main arguments here:
Account munozAccount = new Account(250, "Maria", "Munoz", "110 Glades Road", "Mytown", "FL", "33445");
I'm not sure how to access the generator method, so i'm completely stumped.
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Jan 26, 2014
One of my friend asked me that which will load first static variable or static block ? My answer was to static variable.. So he gave me two program and said to differentiate between them
1st program
public class Test {
public static void main(String args[])
{
System.out.println(Test.x);
}
static {
System.out.println(Test.x);
[Code] ....
Output of this :
90
90
I tried to decompile the byte code and found it's same for both the above equation. How to differentiate between them. I am confused when the static variable will initialised.
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Jul 14, 2014
One class having two method one as static n another as non-static, 2 threads are there t1 is accessing the static method and t2 the non-static method is it possible n both are sharing the same object.
I now we have two kinds of lock one is object level lock and another is class level lock
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Oct 21, 2014
package Experimentation;
import javax.swing.*;
import java.awt.event.*;
public class SimpleGUI1B implements ActionListener {
JButton button;
public static void main(String[] args) {
SimpleGUI1B gui = new SimpleGUI1B();
gui.go();
[code]...
This is a program from Head First Java! since main is static it shouldn't be able to call non-static methods because statics do not use any instance variable values but in the above program we're call a non-static method go() how is it possible?
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