How does the keyword this in the CoffeeSize class refer to the size of the coffee ? I am also confused as to how the CoffeeSize constructor comes into play to determine the cost.
public class Test
{
public static void orderCoffee(CoffeeSize size)
{
size.print();
}
public static void main(String[] args)
{
orderCoffee(CoffeeSize.SMALL);
}
[code]....
how to refer to objects die1 and die2 in the PairofDie class from the SnakeEyes class and what to do.
public class Die {
private final int MAX = 6;
private int faceValue;
private int sum;
//private int faceValue2;
public Die(){
faceValue = 1;
[code]....
I try to get the following code to work. I made a class(Rechthoek) with a constructor and getters and setters.Now, I am trying to make a second class which should create several "rechthoek" objects (setting values in the code of the Rechhoekapplicatie class -->which also acts as main class). However I can't seem set the values in the code; the setter methods won't do it.
I treid: Rechthoek.setLengte() but for some reason the program tells me I need a method setLengte, but I already have a settermethod (setLengte) for it! I do not get it.
Class1:
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package Domein;
[code]....
Created a java.sql.connection object. Refering those obj inside public void run() { } If i declare as final inside a method, i can't refer those outside method due to scope. Cannot refer to a non-final variable dbConnObj inside an inner class defined in a different method...
View Replies View RelatedWhat is the difference between the static keyword and transient keyword?
View Replies View RelatedI have a simple classes here one is interface and another one is abstract class when i try to compile them abstract class is givving compilation error.
public interface MyInterface{
public void getName();
public void getName(String s);
}
public class HelloWorld{}
abstract class SampleClass{
[code]....
accdg to this: [URL]....
we can use EL expression as follows:
${pageContext.request.contextPath}
but there's no instructions as to how I will set its value.
And also, what would happen in case I refer 2 css files in my jsp and both defines the following:
CSS 1 :
body { background-color: #fdf5e6;
font-size: 810px;
}
CSS 2:
body { background-color: #fdf5e6;
font-size: 50px;
}
I'm just putting together a little 'horse racing' program while I'm learning Java, and I have a class called Race that creates an array list of thorougbred horses called field, and asks the user to enter then names of the each horse in the field, with a maximum of 14 horses. The problem occurs with the current code that I have:
import java.util.*;
public class Race {
RaceHelper helper = new RaceHelper();
ArrayList<thoroughbred> field = new ArrayList<thoroughbred>();
public void setField() { //enter the horses in the race and determine the size of the field
[code]....
the statement of the index position and current size was for me, so I could see what was going on.What I don't understand is the while loop. not that the class doesn't compile and run (you can see that it does), it's the output. Why does the <= sign allow one more entry and increase the size of the field to 15?
Less than or equal to 14 should give a maximum field size of 14, right, With the starting object at index position at zero and going up to 13, for a total size of 14 thoroughbred objects if I just use while (field.size()<14) or a for loop, then the output is fine; it allows a max of 14 entries and prints the results. I thought it had something to do with the size being zero based, but that doesn't seem to matter -- unless it does matter and I'm missing it. why the comparison I'm using produces this output? a field of 14 horses shouldn't matter whether it's zero or 1 based, as long as the size of the field is 14, so why the extra entry with this while condition?
Suppose I have
class A {
public void speak() {
System.out.println("I am class A");
}
}
class B extends A{
public void speak() {
System.out.println("I am class B");
}
}
class C extends B{
public void speak() {
System.out.println("I am class C");
}
}
Why this doesn't work while A is a super type of B ?
public static void insertElements(List<? super B> list){
list.add(new A()); //not OK, why?
}
Why java uses the keyword extends when setting the bound of a type parameter(Generic) to an interface. I think using the keyword implements is more intuitive.
public static <T extends Comparable<T>>
why use extends? and not implements.
int countGreaterThan(T[] anArray, T elem) {
int count = 0;
for (T e : anArray)
if (e.compareTo(elem) > 0)
++count;
return count;
}
I know if I want to set multiple bounds I will use extends keyword, and I will concatenate the bounds using & operator.
Is this a design decision to always use extends keyword to set bounds?
I've come across something that i'm not overall sure about regarding the static keyword in Java.I'm making a vertical scrolling game where the player simply shoots enemies and they shoot back as they fall, dropping items if they die such as power ups and coins. I have an enemy called Bat and this is the bullet creation code in the update method:
if(oldPlayerY + 220 > posY && getBulletDelay > 0.90f){
batBullets.add(new Bullet(posX + 10, posY - 10));
getBulletDelay = 0;
}
The method is creating a new bullet object and it then adds that to the arraylist called batBullets, which is simple enough. I then need to access this arraylist in the main game update class so I can render those bullets on the screen, even if the bat dies. I was always taught that you use the static keyword when you need to access something from the class that doesn't require an object. Because of this, I have the following code.
for(Bullet bullet : Bat.batBullets){
bullet.setY(bullet.getY - 5); // Set the bullet to fall
renderMap.getSpriteBatch().draw(bullet.batBullet(), bullet.getX(), bullet.getY()); // render the bullets
}
This seems perfectly fine to me because I need to access the batBullet arraylist and it doesn't make sense to create a new bat object as I already have random spawning in place for them.
I am attaching a document which shows the current state of my registry.What I want to know is if I can [safely] delete the JavaSoft folder with all lower subfolders, then re-install jdk1.6/0_31 which, I am told, is the current version being used here by developers.According to others on the development team (not my team), there COULD be something in the registry that is preventing both the installation of java jdk AND its uninstallation.Since I cannot seem to attach any kind of document.
View Replies View RelatedI need creating a java keyword program that can encipher and decipher a message using the provided keyword.
The keyword is :javbean
I have attached the message text as well...
public class Caesarcipher
{
public static final String ALPHABET = "abcdefghijklmnopqrstuvwxyz";
public static void main(String[] args)
{
String theKey = "JAVBEANDEFGHIJKLMNOPQRSTUVWXYZ";
String text= "message.txt";
[Code] ....
message.txt (763bytes)
The super keyword when used explicitly in a subclass constructor must be the first statement but what about if i have a this(parameters) statements ? As the this one must also be the first statement... Does this means that i can have only one or the other ? What about when the super constructor is not explicit (aka implicit ) , can i use the this( parameters) in the same constructor ?
View Replies View RelatedI've been trying for a while to get my exception output to print in a particular form to System.err.
What I'm looking for as output is
KeywordException: edu.cofc.csci221.KeywordException: **Keyword Not Found**
I'm getting
Keyword Exception: edu.cofc.csci221.KeywordException
at edu.cofc.csci221.CheckLine.checkForInvalidKeyword(CheckLine.java:101)
at edu.cofc.csci221.ReadLogFile.main(ReadLogFile.java:47)
The code:
line = scan.nextLine();
try { check.checkForInvalidSymbols(line); } catch (SymbolException sEx) { System.err.print("Symbol Exception: "); sEx.printStackTrace(); }
try { check.checkForInvalidKeyword(line); }catch (KeywordException kEx) { System.err.print("Keyword Exception: "); kEx.printStackTrace(); }
if(check.checkFirstKeyword(line) && line.split(" ")[0].equals(keywords[0])) { System.out.println(line); }
[Code] ....
I'm just unsure of where to go/what to do.
i need to write a method, that passes in an arraylist and a keyword,and display the name of all the people in the arrayList whose name contain the keyword (irrespective of uppercase or lowercase). how to write such a method ??
View Replies View Related//constructor
class Base
{
Base(int a) {
System.out.println("in base"+a);;
}
}
class Cons extends Base
[Code] .....
I am trying to test the instanceof keyword. To do this, I've made a method with a simple logical test like so:
Java Code:
Vehicle vehicle1 = new Vehicle();
public void Type(){
if (vehicle1 instanceof Vehicle) {
System.out.println("Type = Vehicle");
}
else if (vehicle1 instanceof Car) {
System.out.println("Type = Car");
}
else if (vehicle1 instanceof Truck) {
System.out.println("Type = Truck");
}
}
} mh_sh_highlight_all('java');
I wanted to try implementing it into the class definitions for Vehicle, then extend that to Car and Truck, but I'm not sure how to use this test in a general case.
The only way this method works is if I set the test to specifically accept a specific object as a parameter.
I want to test multiple objects, but I'm not really sure how else to do this without simply copy-pasting the logical test multiple times and changing the respective objects that are used as parameters.
I need to search a txt file for a specific keyword and then output all the lines that contain that keyword. Right now I I think I have my search done but I don't know how I would print the whole line.
TextIO.readFile("xxx.txt");
String search;
String word;
int count=0;
TextIO.put("Please enter your search word: ");
search = TextIO.getln();
while (!TextIO.eof()) {
word = TextIO.getln();
count = count+1;
if (search.equalsIgnoreCase(word)==true){
TextIO.put(count + "-");
TextIO.put(word);
Right now it doesnt even let me enter in any values for the search. Not sure what I've done wrong..
I have this very annoying issue with Eclipse (I have the latest version installed). For some reason, every time I use the "default" keyword in an interface, it gives me an error similar to "Syntax error on token default", I deleted the "default" keyword, the error is gone. The same thing happens with "Lambda expression as well", say I have this object like this :
Actions myActions = () -> {System.out.print("Blah blah blah");}; ,
Eclipse also displays the error message similar to "Method body expected after (), delete '->' ". I checked the Java version I have, it is the latest one also ....
Can be :
results = null;
results = new double[2];
results = new double[50];
results = new double[100];
How determine size of this table : System.out.println("table size=",???);
I am asked in my assignment to make a program that accepts a text file as an example a novel and i have to sort each word as a PERSON or ORGANIZATION or LOCATION or O as in Other , example :
Microsoft/ORGANIZATION ,/O Nelly/PERSON !/O '/O
Now we notice that microsoft is and organitzation and "," is Other and Nelly is a person's name and so on ..
Now I am asked to return the numbers of tags in the text which is 4 in our case because we have (ORGANIZATION,PERSON,LOCATION,OTHER)
My question here is my logic true ? And since i made a map of String,String ; Is there any way that i can get the size of the values in our case the values are the organization etc.. ?
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
[code].....
class Father
{
public int a=5;
private int b=10;
[code]...
what is the size of obj from above code?
I am just not sure of some theory in collections, ArrayList and LinkedList maximum capacity depends on the memory allocated to the JVM. But according to few people those list has a maximum capacity of Integer.MAX_VALUE.
According to my experiment, those list has a maximum capacity of Integer.MAX_VALUE since the get method of List accept a parameter of int primitive type (index of element), therefore we can conclude that the maximum capacity of List is equal to Integer.MAX_VALUE.
But what about the Map? get() method of map accepts object(the key of the map). So does it mean that the maximum capacity of Map depends on the memory allocated to our JVM? Or its maximum size is Integer.MAX_VALUE also just like Lists and Arrays? Is there a way to prove it? Is Map designed to hold infinite number of data (disregarding the heap memory space exception)?
And also about Stack, Deque? is it also the same as Map (in terms of maximum capacity)?
Java Code:
import java.awt.*;
import javax.swing.*;
public class addImage extends JFrame {
private ImageIcon img1;
private JLabel label1;
private ImageIcon img2;
private JLabel label2;
[Code] ....
I want to decrease the size of image 2 but code on line 18 is not working why????
I have attached the output ....
I have the textfile which has lines:
A B 2 midterm 100
C D 1 final 90
C D 1 midterm 90
A B 2 final 80
**NO ARRAYLIST IS ALLOWED!** And the textfile is passed into the method. How to get the size for the array non-randomly inside the method from the passed Scanner file?? What if you have lots of numbers of lines, so how could that be done?
I have doubts about this line Exam[] object = new Exam[12];
Java Code:
public static Exam[] readAllExams(Scanner s) throws ArrayIndexOutOfBoundsException
{
String firstName = "";
String lastName = "";
[Code].....