Method Overridden By Class
Sep 4, 2014I would like to know what does it mean when a method is overridden by a class??Like for example when you append an object value to StringBuilder
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Can A Static Method Be Overridden
Aug 26, 2014can a static method be overridden?
View Replies View RelatedThrow Exception In Overridden Method
Mar 19, 2015I am practicing OCPJP ....
import java.lang.*;
class InvalidValueException extends IllegalArgumentException {}
class InvalidKeyException extends IllegalArgumentException {}
class BaseClass {
void foo() throws IllegalArgumentException {
throw new IllegalArgumentException();
[Code] .....
Which one of the following options correctly describes the behavior of this program? And the answer is (definitely) --> The program will print : InvalidKeyException exception, but when i saw the explanation, it tells
It is not necessary to provide an Exception thrown by a method when the method is overriding a method defined with an exception (using the throws clause).
I don't know, but i think it will compiled because the Exception that is thrown by the foo method in DeriDeri class is inherited from unchecked exception.. so it is not necessary to declare throws statement on its method.. and if the exception was checked exception the answer must be different right?
Covariant Return In Overridden Method
Mar 5, 2015 For starters here is my code:
Java Code: class A {
int x=5;
}
class B extends A {
int x=6;
}
public class CovariantTest {
public A getObject() {
[Code] ....
And this is the output I get:
sub
5
I am unable to figure out how this is outputting 5 instead of 6. The getObject method of SubCovariantTest is obviously the one being called, and it returns a new B(). So why am I getting class A's x value? I thought since I was getting a B object returned that I would get B's x value.
Method Overridden In Method Parameter?
Jul 20, 2014I was following a tutorial for libGdx and suddenly became confused by the following syntax:
up.addListener(new ClickListener(){
public void clicked(InputEvent event, float x, float y){
position.y += 1f;
//currentFrame = animation.getKeyFrame(12);
}
});
"up" is basically a text Button:
TextButton up = new TextButton("up", textButtonStyle);
and .addListener is just one of the methods "TextButton" has (actually I think its inherited from "Button" but that doesn't matter).
Basically my question is what's going on inside the parentheses? From what I see its a new instance of "ClickListener" but then suddenly they override an actual method within. Is this simply just a way to override a method from the ClickListener class or is it something else?
Referring To Overridden Method From Supertype Reference?
May 14, 2015If 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.
Selection Of Invocation Of Overridden Method During Constructor Chaining
May 28, 2014I don't understand, why when in the constructor of the superclass A the method init() is called (line 4), the overridden version of the subclass is invoked (line 26) and not the superclass version (line 7):
class A {
public A () {
init();
}
public void init() {
System.out.println("test");
[Code] ....
I would have guessed that above code prints
test
1
But instead you get a NPE (because when the constructor of B is invoked
public static void main(String[] args) {
new B();
}
Then there is first the implicit call to super:
public B() {
s = " ";
init();
}
Which is the constructor of A:
public A () {
init();
}
But here now this init() method is not the version of A ( public void init() {
System.out.println("test");
}) but the overriden version of the subclass (B): public void init() {
System.out.println(s+=s.length());
}...
Which throws an NPE of course, because the initialization of s has not occured yet (it happens only after the implicit call to super() has finished (see public B() {
s = " ";
init();
}))
Data Getting Overridden On Loop After Parsing A Xml
Mar 14, 2015I have an xml with 'n' number of data which i am parsing,for test i hardcoded without looping has below,now the below line is just parsing and showing the data for index '1' ,i need to loop this and i am not sure how can i do this.How do i find the length of obj and loop,i cannot find any method in SoapObject.I used like below but the data is getting overridden after parsing
for(int i=0;i<obj.getPropertyCount();i++) {
KSoap2ResultParser.parseBusinessObject(obj.getProp erty(i).toString(), getReminder);
}
call in another class
public static void parseBusinessObject(String input, Object output) throws NumberFormatException, IllegalArgumentException, IllegalAccessException, InstantiationException{
[code]...
How To Get Overridden Currency Symbol From Windows
Jan 27, 2014How in Java to get the current(overridden) currency symbol from the Windows?
As you know t is possible in Windows (Control Panel->Region->Additional Settings->Currency) change currency symbol to the new one.
For example default is '$' and customer change it to the '€'
And programs (Excel for example) use this new currency symbol, i.e instead of $100 you see €100.
I need emulate similar behavior in Java.
How To Get Overridden Currency Symbol From Windows
Jan 27, 2014How in Java to get the current(overridden) currency symbol from the Windows?
As you know you able in Windows (Control Panel->Region->Additional Settings->Currency) change currency symbol to the new one.
And programs (Excel for example) use this new currency symbol.
I need emulate similar behavior in Java.
Why Overridden Doesn't Apply To Instance Variables
Mar 15, 2014why overridden doesn't apply to variables. However, instance variables are stored inside the object.I ran below program and expected to print "two" but it gets printed "one".
class SupCont {
String s = "one";
}
class Cont extends SupCont {
public static void main(String a[]) {
String s = "two";
SupCont c = new Cont();
System.out.println(c.s);
}
}
Accessing Parent Class Method Using Child Class Object?
Feb 4, 2015I want to know is there any way we can call parent class method using child class object without using super keyword in class B in the following program like we can do in c++ by using scoop resolution operator
class A{
public void hello(){
System.out.println("hello");
}
}
class B extends A{
public void hello(){
//super.hello();
System.out.println("hello1");
[code]....
Error Passing Value Of A Variable From One Class To Main Method Of Another Class
Jan 8, 2014I've 3 classes.
1. Circle
2. GetInputFromUser
3. testCircle
package ABC;
public class Circle {
private double radius;
public double getRadius() {
return radius;
[Code] .....
In the testCircle class, in the line: getRadius = ui1.GetInput();
It's showing the error: The method GetInput(float) in the type GetInputFromUser is not applicable for the arguments ()
And when I do: getRadius = ui1.GetInput(rad);
It's showing the error: rad cannot be resolved
How To Call A Method That Exist Within A Class Into Main Method
Feb 13, 2014I am just trying to test this array, for a locker combination program that involves classes...but the array is printing out the whacky numbers for the location. When I try to call the method in the main, it does not work. How do I call a method that exist within a class into the main method?
public class locker {
public static void main(String[] args) {
CombinationLock();
[code]....
Calling Private Method To Another Method Located In Same Class
Oct 23, 2014I am trying to call a private method to another method that are located in the same class.
I am trying to call prepareString to the encode method below.
Java Code:
public class ShiftEncoderDecoder
private String prepareString(String plainText)
{
String preparedString = "";
for(int i = 0 ; i < plainText.length();i++)
if(Character.isAlphabetic(plainText.charAt(i)))
[Code] .....
Dice Game - Invoking Method In Other Method Of Same Class
Feb 26, 2015I am currently working on a dice game. I have a private method called rollDice and it performs the action of rolling two dice. For my project, I need to create another method called playerRolls and I am supposed to invoke the rollDice method in the playerRolls method and perform actions based off of that. My question right now is how do I invoke a method into another method of the same class?
View Replies View RelatedCalling Method Of Another Class Which Is Implemented By Runnable Class
Aug 11, 2014i am having a problem while calling a method..i am having a class
Java Code:
public class MySer implements Runnable {
public void getMessage(String msg)
{
...,
}..,
} mh_sh_highlight_all('java');
i use the above class in another class
[code]....
Creating Object Of Class And Calling Its Method In Different Class
May 20, 2015In the process of creating a new class, I need to move my main method from the class SaveDate to the class DynamicTest. Below I have listed the code of both classes.The objective is to be able to run my program from the DynamicTest Class. I need understanding the process of moving my main method to a different class and creating an Object of a class and calling its method.
public class SaveData {
private static final Map<String, Object> myCachedTreeMap = new TreeMap<String, Object>();
public static final List<String> getLines(final String resourceParam, final Charset charset) throws IOException{
System.out.println("Please get: "+resourceParam);
if (myCachedTreeMap.containsKey(resourceParam) ) {
// Use the cached file, to prevent an additional read.
[Code] ......
How To Import Class Into Class With Main Method
Mar 3, 2014Im writing a simple program to understand classes and objects. Basically what I have is a file called Program.java where I have my main method.I have another file called Person.java which I want to use to create Person objects. That person can have a name, email adress, phone number, etc.I put both these files in the same folder.in Program.java my first statement is:
Java Code: import Person.java mh_sh_highlight_all('java');
My problem is that when I compile Program.java i get an error message saying that the package Person.java does not exist.So my question is, when you create a class that you want to use for objects, how do you import that class into your class with the main method so that you can use instances of your other class?
Calling Method Of A Class From Main Class?
Aug 31, 2014// Add range to Vehicle.
class Vehicle {
int passengers; // number of passengers
int fuelcap; // fuel capacity in gallons
int mpg; // fuel consumption in miles per gallon
// Display the range.
void range() {
System.out.println("Range is " + fuelcap * mpg);
[Code] ....
I'm compiling it in Eclipse and this continues to show in the console display
Minivan can carry 7. Exception in thread "main" java.lang.NoSuchMethodError: Vehicle.range()V
at AddMeth.main(AddMeth.java:34)
Using A Method From A Different Class?
Oct 25, 2014I have a program that reads some text, and draws or deletes objects on a JFrame according to what I say. My program works fine for the most part. So whenever I say something like makeStuff(star) in my console, a star is drawn on screen. I kept track of types of objects in an ArrayList, and add and remove certain objects depending on the type of text I input. My problem is when I get to the point when there are no more objects of the same type on screen, meaning I keep clearing objects of the same type until there are no more, when I go to draw another object of the same type, it does not draw the object.
I have two classes, one for my console and one for graphical objects to be drawn. Strangely enough if I call clear twice then I can draw which doesn't make a lot of sense. When going through the debugging everything is working right, including the counters I made, and the amount of objects of the same type have the right amount when they are supposed to. I did find a work around by simply making the object in the console program class instead of calling the draw method from the sandbox class but my console class is probably a 1000 lines of code and is far too big already. I just want to use the draw method from the other class. Here are some revelant lines of code as to what I am trying to do:
Console Class
Java Code:
if (cmd.equals("clear") && arg.equals("star")) { //use a boolean for when this part is done
if (starCounter > 0) {
box.undoStar();
starCounter -= 1;
starNum -= box.getWidth() / 6;
[code]....
How To Get To A Method Of Inner Class
Feb 2, 2014Imagine I have a class called Outer that contains a Inner class with a method.
Now there is a second class which wants to call that method:
Java Code: public class Outer {
public Outer() {
Inner inner = new Inner();
[Code].....
Method Name Same As Class Name?
Apr 3, 2015I can't get errors of this code I think the problem is that the first method name is the same as the class name and was wondering what the simplest way to fix that is.
class CreditCard{
int transactionNum;
String merchantName;
double charge;
public void CreditCardMethod(int someTransactionNum, String someMerchantName, double someCharge){
[code]...
Linking A Method From Another Class?
Jun 16, 2014I use the BlueJ software to develop my programs. I am creating a program which holds two data structures; Array List and Binary Tree. I have created a person class which is used to declare variables containing people, this class also contains a method which prompts the user to input 3 characters of a memorable word. These people are created within the array list and binary tree. This actually works in practice, within the program, but i get an error, and i need the program to contain no errors.
In my binary tree class, i want to call this method.I have attached 4 images to this post, an overview of the classes used, a look at highlighted code which is an attempt at calling a method from the person class, and the method contained within the person class itself. Note that the person class is just called "Person". The 4th image is the error being displayed.
[URL]
JSP :: Class Imported But Cannot Use Method
Apr 6, 2014I created a BankCommons java file, compiled nd packaged the class file under WEB-INF/classes/com/onlinebank/..I imported the class in the jsp file as <@page import="com.onlinebank.BankCommons.*" % > I ran it through tomcat....the class is being imported..no error there.....but when i try to use one of the method in the class as : BankCommons.update, ...it throws an error that BankCommons cannot be resolved...
View Replies View RelatedAccessing A Method From Another Class
Apr 1, 2014I have an admin class that needs to access a method of another class and I'm unsure how to do it.
One of the methods in the admin class (DancerAdmin) accesses a .txt file with information in and each line is to be extracted and is to be created as an object of the Dancer class. The information in each line is to then be used to set the variables in the Dancer class.
To set the values the Dancer class has setter methods which I need to access each time a new object is created while cycling through the .txt file. I'm struggling to access these methods from the DancerAdmin class when I run the relevant method.
The snippet of code I have from the method in DancerAdmin is
while (bufferedScanner.hasNextLine()) {
currentLine = bufferedScanner.nextLine();
lineScanner = new Scanner(currentLine);
lineScanner.useDelimiter(",");
dancer.add(new Dancer());
Dancer.setName(lineScanner.next()); mh_sh_highlight_all('java');
I get an error saying non static method setName cannot be referenced from a static content?