I am trying to declare fields as protected String custom.field.1096; in my java class but it does not allow me. Can I not declare the field as above? Is there any workaround to achieve this?
View RepliesI want to have parameters that I use the "void" for, in other words it doesn't return anything.
class code
{
void go()
{
int TestStuff t = new TestStuff();
t.takeTwo(12,34)
}
void takeTwo (int x, int y) {
int z = x + y;
System.out.println("Total is:" + z);
}
}
Suppose you have a generic Dog class of the pet type that implements a DogInterface of the pet type. What is the difference between;
DogInterface<pet> Rex = new Dog<pet>();
and
Dog<pet> Tye = new Dog<pet>();
In what situations might you want to use Rex instead of Tye?
How do you declare methods for a class within the class whilst objects of the class are declared else where?
Say for instance, I have a main class Wall, and another class called Clock, and because they are both GUI based, I want to put a Clock on the Wall, so I have declared an instance object of Clock in the Wall class (Wall extends JFrame, and Clock extends JPanel).
I now want to have methods such as setClock, resetClock in the Clock class, but im having trouble in being able to refer to the Clock object thats been declared in the Wall class.
Is this possible? Or am I trying to do something thats not possible? Or maybe I've missed something really obvious?
I've just been having a go at an exercise where I have to create and use a class called Point, with two fields of type double. I have to create some methods for it, one of which is a distanceTo(Point) method, that calculates the distance to another point. I've tried to keep the distanceTo(Point) method short so have created some other methods to use within the method. My question is about the getDistance() method that I've made. As you can see below, I've given it two parameters, which are references to values within two Point objects (this.x and otherPoint.x).
double distanceTo(Point otherPoint) {
double distanceX = getDistance(this.x, otherPoint.x);
double distanceY = getDistance(this.y, otherPoint.y);
return calculateLength(distanceX, distanceY);
}
So i declared a class in main class but it seems there's error when i compile:
constructor xx in class xx cannot applied to given types
This is my java class:
public class trainer extends person{
String classType;
public trainer(String name, String gender, String address, int id, String classType) {
super(name,gender,address,id);
this.classType=classType;
[Code] ....
And this is the way i declared in main class:
trainer tr = new trainer();
And what i want to do is:
tr.toString();
I don't know why class Object have two PROTECTED method -- clone() and finalize(). And in JUnit's source code, I notice that kent write :public class AClass extends Object {}I really don't understand what diffrient frompublic class AClass {}
View Replies View Relatedhow access levels work from subclasses and other packages, and I have discovered that a class cannot see it's own protected variable from another package which I thought it would be. I know that it says in the java docs "The protected modifier specifies that the member can only be accessed within its own package (as with package-private) and, in addition, by a subclass of its class in another package." but I thought that would also include it's own class.
Java Code:
package food;
import food.fruit.*;
public class Food {
protected int protecte = 5;
private int privat = 5;
protected void method(){
[Code] ....
I've just started, so right now I'm reading about declaring enums, the book lists the following code
enum CoffeeSize {
//8,10 & 16 are passed to the constuctor
BIG(6), HUGE(10), OVERWHELMING(16);
CoffeeSize(int ounces){ //constructor
this.ounces = ounces;
[Code] .....
I'm assuming that code to be in a same file since enums can be declared within and outside a class, so I saved it into a file named "Coffee.java", it compiles just fine from command line but when I try to execute "java Coffee" it throws "Error: Could not find or load main class Coffee"...
How to read Password protected Excel file using java. Actually i read normal excel file(without password protection) successfully, using some standard codings with support POI jars. But i am unable to read password protected xls file.
View Replies View RelatedWhat should be the code if i want to input a different string in case of the typed string. The case is : I have a predefined string S = "Peter,please answer my question" and now when i input another string inside the text field character by character i want characters from the string S to enter instead of the input string. In short, the input string should be disguised as string S.
View Replies View RelatedI have a problem with several java applications. When I start them Java wants to connect to the certificate authority, to check if the certificate is still valid and not on a blacklist.
The problem is: my whole internet is behind a password protected proxy. If I open my browser i get a windows with username and password. I enter it and internet in the browser works. But for Java it isn't working, because I see no point, where I can enter the password and username for the proxy. I can enter the proxy ip and port in the java settings, but not the password and username. So I get a error screen from java, telling me, that java could not connect. I can disable the check in the java settings, but I don't wont that.
Is there a way to tell java, that java uses my proxy with my password and username? I already googled this problem and found nothing except tutorials for connecting with proxy in the java code. But these applications are not from me, I can't change the code ...
I have an assignment to write a Payroll class that uses the following arrays as fields:
-employeeID - An array of seven integers to hold employee identification numbers. The array should be initialized with the following numbers: 5658845 4520125 7895122 8777541 8451277 1302850 7580489
-hours - An array of seven integers to hold the number of hours worked by each employee
-payRate - An array of seven doubles to hold each employees hourly pay rate
-wages - An array of seven doubles to hold each employees gross wages
The class should relate the data in each array through the subscripts. For example, the number in element 0 of the hours array should be the number of hours worked by the employee whose identification number is stored in element 0 of the employeeID array. That same employee's pay rate should be stored in element 0 of the payRate array. In addition to the appropriate accessor and mutator methods, the class should have a method that accepts an employee's identification number as an argument and returns the gross pay for that employee. Demonstrate the class in a complete program that displays each employee number and asks the user to enter that employee's hours and pay rate. It should then display each employee's identification number and gross wages. Input Validation: Do not accept negative values for hours or numbers less than 6.00 for pay rate.
I'm off to a great start, however I'm stumped on how to pass the payrate for each employee into the array, then grab that data in order to calculate the gross wage for each employee and store THAT in its own array. THEN I'll have to output that data to each employee.
Code is shown below.
import java.util.Scanner;
import java.text.DecimalFormat;
public class PayrollProgram {
public static void main(String[] args) {
Scanner userInput = new Scanner(System.in);
DecimalFormat df = new DecimalFormat("0.00");
[code]....
I'm having a hard time with this problem, this is what I have, but I can not use two integers, I have to use one integer and a string...
This is the question:
Write a method called printStrings that accepts a String and a number of repetitions as parameters and prints that String the given number of times. For example, the call:
printStrings("abc", 5);
will print the following output: abcabcabcabcabc
This is what I attempted:
public class printStringsproject {
public static void printStrings(int abc, int number) {
for (int i = 1; i <= number; i++) {
System.out.print("abc");
}
}
public static void main(String[] args) {
printStrings(1, 5);
}
}
how to differ between fields that are not exists to fields that are null? because in my api when someone wants to delete a field he sends null instead of a value. and if he doesnt want to effect this feild he doesnt send it.
{
"a" : {"1","2"},
"b" : "hello"
}
{
"a" : null,
"b" : "hello"
}
{
"b" : "hello"
}
I have to create a constructor with eight parameters containing both string and integers.the variables were supposed to be entered by user. but when I try to create an object of the class the IDE post error messages about the constructor.
public class hfiledriver {
//the class name is hfile
//after the main method I try creating an object of the class
//after prompting the user to enter the data
hfile hfile= new hfile(firstname, lastname, gender, age, weight, height);
}
The one problem in my book was to create a constructor for different shirt features, which I did and ran successfully. Out of curiosity, I also added other methods to see if it would run if the parameters were different from the constructor. It keeps giving me a constructor error. So, my question is, am I able to create a class that uses a constructor with parameters and other methods without errors? I'm guessing there's no reason to since it would be wasted space since the constructor could do it but was just curious if it's possible.
Is everything from the constructor down (in the class) and Shirt.oneShirt (in the main) just a waste of time?
Here's my example:
public class Shirt//class name.
{
int collarSize;//data field.
int sleeveLength;//data field.
int pocketNumber;//data field
public final static String MATERIAL = "cotton";//final data field for material.
public Shirt(int collarSize, int sleeveLength, int pocketNumber)//start of constructor.
{
[Code]...
I defined a java class thus:
class Info{
public String name;
public String version;
public String arch;
double CPUSpeed;
double ranUtil, CPUUtil;
};
But each object of such a class takes many bytes. How can I limit it to one fourth of a Kilo-Byte?
There are two versions
1. The words remain in their places but the letters are reversed. Eg I love you becomes Ievol uoy
2. The words are also reversed. Eg I love you becomes uoy evol IWrite a program that use the java String class methods.
When i run the program it doesn't show all the text fields and labels and stuff but when i click btnTest_1 and go back to btnTest everything appears...
Java Code:
import javax.swing.*;
public class Frame extends JFrame{
private JTextField textField;
private JTextField textField_1;
public Frame(){
setTitle("Multifunctual Calculator");
[Code] ....
I have created an application using hibernate and struts.In which a form is created where the user will enter all its personal details(for e.g name ,phone no. and address).
Here for address I have used textarea and whenever user enters the address, sometimes it can be a long string also.
So the problem is if a long string is entered then while displaying that ,address comes on single line and the page is stretched.
how to break this single string into mutiple lines in java class?
This program is basically complete. It compiles and runs. It is a college course assignment that I pretty much completed but for the last part in which I'm suppose to change the values of all fields and display the modified values using a toString method. Modifying the values of the fields is where I am stuck. I don't think I need to create a new text data file to do this. The instructor only asked that all the values of fields be changed and this was the last part of the assignment so I don't think it involves creating additional ObjectOutputStream and ObjectInputStream objects. I'm getting a NullPointerException error on line 161.Here is the code. I'm also including the input data file.
//create program so that objects of class can be serialized, implements interface Serialiable
//create constructor with 4 parameters with accompanying get and set methods, Override toString method
//create text file with 5 records, create Scanner object,ObjectOutputStream, and ObjectInputStream
//create new ItemRecord object, change values of all fields in ItemRecord object using object's set methods
//modify ItemRecord object using toString method
[hightlight =Java]import java.io.Serializable;
public class ItemRecord implements Serializable
[Code] .....
This is the error message:
----jGRASP exec: java ItemRecordReport
Item Cost Quantity Description
Number
A100 $ 99.99 10 Canon PowerShot-135
A200 $149.99 50 Panasonic-Lumix T55
A300 $349.99 20 Nikon- D3200 DSRL
A400 $280.99 30 Sony- DSC-W800
A500 $ 97.99 20 Samsung- WB35F
Exception in thread "main" java.lang.NullPointerException
at ItemRecordReport.main(ItemRecordReport.java:161)
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.
Here is the data file:
A100 99.99 10 Canon PowerShot-135
A200 149.99 50 Panasonic-Lumix T55
A300 349.99 20 Nikon- D3200 DSRL
A400 280.99 30 Sony- DSC-W800
A500 97.99 20 Samsung- WB35F
Here is the data file for the modified field values.
B100 98.00 10 ABC1010
B200 97.00 15 DEF1020
B300 96.00 10 GHI1030
B400 95.00 05 JKL1040
B500 94.00 01 MNO1050
I am trying to pass parameters from he following HTML file to an applet. the applet is not initializing and the iam getting the following error on the console. I also have both the html file and and the java applet under the same source file in eclipse.
java.lang.NumberFormatException: null
at java.lang.Integer.parseInt(Integer.java:542)
at java.lang.Integer.parseInt(Integer.java:615)
at applet.DisplayMessage.init(DisplayMessage.java:16)
at sun.applet.AppletPanel.run(AppletPanel.java:434)
at java.lang.Thread.run(Thread.java:745)
Here is the html file
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
[Code] ....
I'm trying to create a Servlet that takes input from a form and process it and insert it in database.tablename.
My MAIN ISSUE IS WITH THE NUMBER OF COLUMNS THAT WOULD BE DYNAMIC AND THUS CANT RECEIVE THE PARAMETERS IN STATIC CODE.
Here is the form code
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<form action="Test" method="post" />
<table width="90%" border="1" cellspacing="1" cellpadding="1">
[Code] ....
And here is the Servlet
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import java.io.*;
public class Test extends HttpServlet {
[Code] ....
This is the basic code structure and I'm trying to figure out this special case with handling the multiple parameters:
I don't want to use String []a=request.getParameterValues("studentname"); as hard code. The reason being the number of rows will be diyamic and I would like to get the column name and then then use an array of string to take values. But how can I connect these to form a query so that the rows goes on inserted one after other.
I am new in java. Is there any difference between protected or default when we are talking about one package?
View Replies View RelatedI was just wondering.. my understanding from everywhere I have read is interface cannot be private or protected (not at the top level) but when we declare an interface without any modifier it is default.
We know default modifier has more restricted access than protected.. public > protected > default > private
Now since an interface can be public and default then why not protected as clearly if they were allowed to be protected they could be implemented by a subclass..?
While typing this question I figured how would an interface know which is it's subclass? that is why Java allows only public i.e. any class can implement it or default i.e. any class within the package can implement.. am I right?