public class {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
double[] numbers = new double[10];
System.out.println("Enter " + numbers.length + "numbers");
for (int i = 0; i < numbers.length; i++) {
numbers[i] = input.nextDouble();
[Code] .....
I am trying to reference the input "numbers[i]" to my mean method, how do i do that?
I have a Homework that's on Polymorphism and inheritance. The problem is of a triangle class. The super class is GeometricObject and the subclass Triangle. I have the parent and child classes compiling, now it's the test program.
The problem is the examples in the book don't show anything about prompting input for objects. The objects in the Triangle class are: side1, side2, and side3 and so I created objects in the test: Triangle sideOne = new Triangle(); . I've tried to compile but jGrasp doesn't like anything I do and the instructor in my class hasn't shown us examples yet. Can I prompt input for reference type and not just primitive type?
If a method is overridden but you use a polymorphic (supertype) reference to refer to the subtype object with the overriding method, the compiler assumes you're calling the supertype version of the method.
is this true? maybe i'm misunderstanding it, but i thought the JVM looks at the object at run time and checks the object type. the context of the quote is about checked exceptions, but it seems like the statement should stand regardless of context. but this doesn't back up my experience. for example:
public class Test{
public void print(){
System.out.println("Super");
} public static void main(String[] args){
Test t = new SubTest();
[Code] ....
Will invoke the subclass method. like i said, maybe i'm missing something.
I faced with a problem, when I use method reference as a function in Collectors.groupingBy I get an error: "no suitable method found for collect". But! if I replaced method reference with a lambda expression everything works fine.
Here is the code sample:
interface Iface{
public int getPropertyOfClassA();
public void setPropertyOfClassA(int propertyOfClassA);
}
class A implements Iface{
private int propertyOfClassA;
[Code] ....
Change "C::getPropertyOfClassA" with "objC -> objC.getPropertyOfClassA()" and it works!
I am trying to implement the following example to override the equality and hashCode method if the class has reference type member. I do get the expected result "true" for equal and "false" for non-equal objects. But the print statement in the Circle's equal method is not executed when the objects values are not equal. I don't know what i am missing, though i get the equality result "false" as expected for non equal objects.
class Point{
private int x, y;
Point (int x, int y) {
this.x =x;
this.y = y;
[code]....
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".
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] ....
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'.
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?
View Replies View RelatedI have a get grid method that gets input from the user. I also have a display grid method that is supposed to display the get grid method but it doesn't. What do I do to make the display grid method work properly. I am not allowed to use a main method.
private int a1,a2,a3,a4,b1,b2,b3,b4,c1,c2,c3,c4,d1,d2,d3,d4;
public void getGrid ()
{
System.out.println();
System.out.print ("Enter Row 1: ");
a1 = i.nextInt();
a2 = i.nextInt();
a3 = i.nextInt();
a4 = i.nextInt();
System.out.print ("Enter Row 2: ");
b1 = i.nextInt();
b2 = i.nextInt();
b3 = i.nextInt();
b4 = i.nextInt();
[code]....
Create an equals method that takes an object reference and returns true if the given object equals this object.
Hint: You'll need 'instanceof' and cast to a (Geocache)
So far I have:
public boolean equals(Object O){
if(O instanceof Geocache){
Geocache j=(Geocache) O;
if (this.equals(j)) //I know this is wrong... but I can't figure it out
return true;
}
else return false;
}
I think I have it correct up to the casting but I don't understand what I'm suppose to do with the this.equals(). Also I'm getting an error that I'm not returning a boolean... I get this all the time in other problems. I don't get why since I have to instances of returning booleans in this. "returns true if the given object equals this object" makes no sense to me. I assume the given object, in my case, is 'O'. What is 'this' object referring to?
I need to pass user input from the main method, which is then validated using another method that is returned as a valid score, and then I pass the valid input to another method that stores the data in an array. The array is initialized within the method. I tried to use an if-else statement to initialize the array, because I originally did this at the beginning of the method. I soon learned that I was creating a new array everything I accessed the method. Needless to say, this isn't working either.
public static void main(String[] args) {
int judges = 7;
float[] validScores = new float[judges];
for (int i = 0; i < judges; i++) {
float score = -1;
[Code] ....
My OrderCalculator class is throwing an exception. The input from my HourPanel that is supposed to add to my OrderCalc is cooperating.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.text.DecimalFormat;
public class OrderCalculator extends JFrame
{
private JobPanel jobs;
private HourPanel rate;
[Code] .....
Create a method called mirrorImage, which takes two integer arrays as input parameters. You may assume that the two actual parameters have the same length. Your method should return true if the arrays are the reverse of each other. Otherwise mirrorImage should return false.
Examples:
data1:{1,2,3}
data2:{3,2,1}
==> true
[code].....
I'm pointing a place outside of the array or something
runtime error (line 8, column 0): java.lang.ArrayIndexOutOfBoundsException: 10
-> array.ArrayQuestions.mirrorImage()
This program contains a superclass and a subclass that will gather the following information from the user:
name, address, phone number, and customer number.
Everything works fine except that I have to create a boolean method in this program that is required to determine based on user input whether they want to be added to a mailing list.
I cannot get this method to work with main, each time it is called it will always return the value but main will constantly read the last statement (else, where it will read "not wanting to be added to the mailing list).
The only way I can get this part of the program to work is by adding an equals method in main that ignores the case, but I am required to write a boolean method so this is not allowed.
Superclass:
public class Person
{
private String name;
private String address;
private String phoneNum;
public Person(String pName, String add, String number)
{
name = pName;
address = add;
[Code] ...
I am doing a Junit test case, but I keep having issues with AssertEquals ( object expected, object actual). I don't know how to reference the other actual object so that it can compare to the expected.
public void add (Distance d) throws CustomException
{
//I can also convert feet to inches and add all inches together and then divided inches to feet and inches
Distance result = new Distance();
int newFeet = this.feet + d.getFeet();
int newInches = this.inches + d.getInches();
if(newInches > 11)
{
newFeet = newFeet + (newInches/12);
[Code]...
I don't really know what this means and it is sending an error when I try to run my program I am trying to set the x and y value (Int x and int y) to setVisible false at a specific time in my game but it keeps sending the error that int is not a reference type.
View Replies View RelatedI'm fairly new to Java, I'm very experienced with C++ and C# in which you can pass by reference - extremely useful. Take for example this bit of code in C#:
class MyClass
{
public MyClass(int i)
{
m_i = i;
}
public int m_i;
[Code] ...
Just at the end of this program x.m_i will be equal to 8. As far as I can see this is not possible in Java: you can't pass a double by reference, using a Double will kick in the autoboxing so that won't work either. The only "solution" in Java would be to pass in a double[] (of length 1) or to make a wrapper class, both nasty solutions because a user may want to just hold a double as a member of their class just as I have, for reasons such as not allocating more memory for a class and generally not being bloated.
I am passing input from the user to a method that will initialize an array of the data (scores in this case). The method is filling the entire array with the last input value.
array initializer method
Java Code:
public static float[] inputAllScores(float validScore) {
float[] diverScores = new float[7];
for (int i = 0; i < diverScores.length; i++) {
diverScores[i] = validScore;
}
return diverScores;
} mh_sh_highlight_all('java');
[Code] .....
I am making an MVC program and I am not allowed to put the action listeners in the view class. I was able to get one button working fine but since I am unable to reference them I cannot give them both individual responses.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Controller {
HobbyList model;
ListView view;
[code]....
I know in C++ It's possible to pass by reference but what about java?
For example, can i pass the address of a health variable into a Ninja class and then
Since Ninja inherits from an enemy class pass the health into the enemy class and within there have a function that returns that same health address and takes 5 from the health returning 95.
I passed my abstract class private final reference to another concrete class and I used abstract class reference as parameter to that concrete class constructor and in my main method and null to that parameter then only that program executes correctly...i placing my code below ..if there is any error tell me where is error occurring then i will check my code...i think my code is right but little bit doubt abstract class concept.
{
}
class concept1 extends concept
{
private final concept parent;
public concept1(concept aparent)
{
parent=aparent;
System.out.println(parent);
}
public static void main(String args[])
{
//concept p=new concept1(null);
concept c=new concept1(null);
}}
When I write a statement such as:
myType x;
This means that x is a reference to objects of type, "myType" and no memory has been set aside for an instance of this object. I think it's true that x also has the starting memory address of this object.
What I feel uncertain about is if x is telling the JVM(?) where it can find the starting address of this object, why do we care about the type that x is?
i.e., if we assign x to an object totally unrelated to this type then the compiler would complain - correct? If so, how come, since all x is doing is telling the JVM(?) where to find your object (via the address it contains).
I suppose all, hy a reference has a type associated with it if all the reference does is point you to the object?
I am currently learning Java basic concepts and this is a very simple code which produces error depending on the way I write. It is as follows:
package testPackage;
interface ArrayInsideClassShock {
}
class Check{
ArrayInsideClassShock var[]; //Error line
var= new ArrayInsideClassShock[10];
}
Error in eclipse:Syntax error on token ";", , expected
But if I write it as:
package testPackage;
interface ArrayInsideClassShock {
}
class Check{
ArrayInsideClassShock var[]=new ArrayInsideClassShock[10];
}
It doesn't show any error.
what these mean with examples..
1. A reference variable can be of only one type and once declared, that type can never be changed(although the object it references can change)
2. A reference is a varaible ,so it can be reassigned to other objects(unless the reference is declared final)
3. A reference variable's type determines the methods that can be invoked on the object the variable is referencing.
4. A reference variable can refer to any object of the same type as the declared reference , or - it can refer to any subtype of the declared type.
5. A reference variable can be declared as a class type or an interface type. If the variable is declared as an interface type, it can reference any object of any class that implements the interface.
I don't understand why following code when executed returns false
String s1= " string".trim();
if(s1 == "string"){
System.out.println("true");
}
else{
System.out.println("false");
}