Default Method In Interface
Feb 7, 2014interface I1{
void show();
void display();
default void put(){
System.out.println("I am from interface I1");
[Code] ....
This code is not working..
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If Interface Can Be Default Then Why Not Protected?
Mar 9, 2014I 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?
Interface - Syntax Error On Token Default
Jul 14, 2014I am following this article : [URL] ....
And I have created 4 different types of Interfaces and Classes
Interface:-Flyer,Mythical
Class:-Horse,Pegasys.
But on Interface
I am getting error on line
default public String identifyMyself()
"Syntax error on token "default" delete this token"
Here is code for all 4 interfaces and classes
public class Horse {
public String identifyMyself() {
return "I am a horse.";
}
}
public interface Flyer {
default public String identifyMyself() {
[Code] ....
Default Values Passed By JVM In Order To Call Main Method
Aug 27, 2014For the below program what are the default values passed by the JVM in order to call main() method
class program
{
public static void main(String[] args)
{
System.out.println(args[0]);
System.out.println(args[1]);
}
}
Servlets :: HTTP GET Default Method For Web Browsers Contacting Web Servers?
Sep 5, 2014I am running a test servlet on Tomcat and have implemented different behaviours for the doPost and doGet methods. When I access from the browser, only the doGet method gets called ultimately.
The Firefox developer tools show me a GET request from the browser to my Tomcat instance. Do browsers ever call the POST http method? How could I make this happen?
Eclipse Does Not Recognize Default Method Keyword And Lambda Expression
Jun 2, 2014I 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 ....
Implement Method Inside Interface
Sep 3, 2014if i call a class that implements an interface the method inside the interface will be triggered automatically by the compiler or happens only in the observer pattern? i keep simple to be surr the message came across, a typical example would be a listener on a button, or a collection that calls comparator)
View Replies View RelatedMethod Declaration - Partial Interface Implementation
Sep 3, 2014I have one interface with three(more than one) method declaration. In the subclass that implements it I want to define only one method not all three not even blank definition of them.Is there any keyword or method for that. How to do it? Is it possible to do it? In GUI we use adapter classes to achieve it. What for console application?
View Replies View RelatedCall Method In All Objects Which Implement Certain Interface
Apr 15, 2015 if some of you worked with Unity Game engine (C#) the idea is that game has main loop and once per cycle it call for example Update() method in all objects which implement certain interface.
I would like to repeat such pattern in Java for another another program, not even game related, but I would still need a main loop and event driven behaviour with async call backsSo question is how to implement the fallowing scenario:
Imagine i have interface which implement some methods and one of them is Execute()
I have the main controller class which implement main loop, also multiple other classes which implement the same interface with method Execute(). How can i call this Execute() method on all objects which implement that interface each loop cycle?
Should i keep and track reference of each object which was implemented with this interface and go through inner "for" loop trough each reference and call manually Execute() method in each of them?what if each object implementing interface have to run Execute() method simultaneously? in parallel independent from each other?
Referring back to Unity engine and their Update() method - there is exactly the same situation:you can have multiple objects with script attached, thats script implement interface which has multiple methods and one of them is Update() and once per cycle all objects with that Update() method will be executed in parallel independently
Java Interface - Implement Method In Another Class
Sep 17, 2014So I created an interface which has the method
int getCalls();
I am trying to implement this method in another class but I'm not sure how to do so. My attempt is:
public getCalls(){ return getCalls(); }
When I run the program it sends the following exception:
Exception in thread "main" java.lang.StackOverflowError
at FibonacciForget.getCalls(FibonacciForget.java:14)
and it highlights the [return getCalls();] part.
What is the correct way to implement the getCalls() method?
Method Implementation Declaring Exception Other Than That Declared In Interface
Aug 31, 2014The 2 minute drill from page 69 SCJP kathy and bert book, says regarding Interfaces, that - "A legal nonabstract implementing class must not declare any new checked exceptions for an implementation method."
When I try the below given code in eclipse , it does not throw any errors . (Here I have tried to throw NullPointerException from testFunc whereas the interface function throws IllegalStateExc)
package abstracttesting;
public class StaticCheck implements check{
public void testFunc() throws NullPointerException{
// TODO Auto-generated method stub
} public static void main(String[] args) {
// TODO Auto-generated method stub
}
}
interface check{
void testFunc() throws IllegalStateException;
}
Trying To Implement Interface - The Method DoSomething Is Undefined For The Type B
Dec 2, 2014Let's say we have situation like this:
abstract class A
class B extends A
class C extends B
class D extends C implements SomeInterface
I'm trying to implement a method "doSomething" declared in SomeInterface in class D. While trying to call doSomething in main I get the error message ”The method doSomething is undefined for the type B”
This is my code i main:
B container = new D("1,2,3,4,5,6,7,8");
System.out.println(container.doSomething());
I need container to be an object of type B, because it goes later into a list of type B. According to what I've been told, the only file I need to edit to make this work is class D.
Method That Return Instance Of A Class That Implement Iterator Interface
Apr 14, 2015I have been researching the Iterator and making a class implement iterable. I have seen this example shown below and was wondering how I could change this so that iterable() is not called upon in the main. I would like to be able to make a method that returns an instance of a class that implements the Iterator interface hopefully an inner class. This is because my program will not have a main and will be supplied with a main that includes a new Object with will use the iterator method.
import java.util.*;
public class IteratorDemo {
public static void main(String args[]) {
// Create an array list
ArrayList al = new ArrayList();
// add elements to the array list
al.add("C");
[Code] ....
This is all I have been able to understand from what I want to do. This does not work and this is what I am trying to achieve
public class MyArrayList implements Iterable {
public static final int DEFAULT_SIZE = 5;
public static final int EXPANSION = 5;
private int capacity;
private int size;
private Object[] items;
[Code] ...
Interface Extends More Than One Interface
Jun 9, 2014Below code gets printed as output?
public interface I1 {
public void method();
}
public interface I2 {
public void method();
}
public interface I3 extends I2, I1 {
[Code] ....
No Default Constructor
Nov 2, 2014The LocalStudent class inherits the Student class. The IDE states an error of "no default constructor in Student class".I understand that if a LocalStudent object is created, the default constructor of its superclass (aka Student class) will be called implicitly.there is no LocalStudent object being created, so why is the default constructor of Student being called ?
The default constructor of LocalStudent is also overloaded by the created no-arg constructor containining subjects = null; . So there is no call to the superclass default constructor from the default constructor of LocalStudent.
public class Student {
private char year1;
public Student(String name, char year){
year1 = year;
}
public char getYear(){
return year1;
[code]...
Difference Between Protected Or Default
Mar 28, 2015I am new in java. Is there any difference between protected or default when we are talking about one package?
View Replies View RelatedHow To Put Default Int / Float For JTextField
Feb 4, 2014Will I'm tying in my code to set a default number for the JTextField that when the user decide not to put any numbers. Like let say that I want the textfield set to 0 , so then the user do not file it it won't make any problem to the program because its already has a default number.
if (stringGQ != null && stringGW != null && stringGP != null){
stringGQ = gMQ.getText();
stringGW = gMW.getText();
stringGP = gMP.getText();
weightPrice_1M = Double.parseDouble(stringGW) * Double.parseDouble(stringGP);
[Code] .....
Note: This is a small part of my code. when I leave it empty it take the 0 as a value, However, when I write in text field it also take the value of a 0 and the finalTotal is also = to 0.what I'm doing wrong.
Default Literal For Boolean
Mar 31, 2014what is default literal for Boolean data type?
View Replies View RelatedArrayList - Default Size As 10
Oct 8, 2014ArrayList l = new ArrayList();
System.out.println(l.size());
When I running the above code in eclipse the console show me the result as "0". So how to rectify this code to find default size as 10.
Default Access Modifier
Mar 21, 2014class Course
{
String courseName;
}
class Entry
{
public static void main(String[] args)
{
Course c = new Course();
c.courseName="java";
System.out.println(c.courseName);
}
}
I have defined these two classes under same java project in Eclipse IDE with no package. Above two class are having default classes. class Course is also having a instance variable courseName with default access. So when we try to compile the Entry class it will give the errors while accessing the instance variable courseName on Line 6 and 7. As both the classes are having default access modifier. class Course is not visible to class Entry, then why we do not get any compilation error while creating the object of class Course on line 5?
Initialization And Default Values
Mar 20, 2015I have a question related to q44 of Examlab.
public static void main(String... args) {
String i;
// String i = null; that would compile
if (i == null) {// this line does not compile as i was not initialized
System.out.print("A");
} else {
System.out.print("B");
i = "A";
main("A", "B");
}
}
Why does the above code not compile although the statement String i should lead to an initialisation of i to the value of null which is the default value for Strings.
Default Initialization To Appropriate Value By Compiler
Feb 20, 2014I remember reading Instance variables & local variables (in methods) are initialized to appropriate value by the compiler.
Is this true for static class variables and variables in nested classes ?
Change Default Program For Extension
Jan 22, 2015I want to programmatically change the default program which an extension is opened in. So .resantic extensions for example to run in my jar file when I double-click on it. I know i need a bat file or exe file because i can't directly run the jar file. But i was wondering if its possible to run it if its an executable jar file. Else i can just make a bat file that runs my program. Also how can i on double click send the path to the file that was clicked in the args[] array so i can open the actual file aswell instead of just opening the program?
View Replies View RelatedPrinting Default Value Of Int - When Is Variable Initialized
Nov 12, 2014In the following code the print method prints the default value of int(zero) for the first time even when the variable i has been assigned a value of 4. Why?
class A1{
A1()
{
System.out.println("Inside constructor of A1()");
print();
}
void print()
{
System.out.println("A");
[Code] ....
Output:
Inside constructor of A1()
0
Inside constructor of B1()
4
How To Add Variables And Default Values To Arraylist
Mar 23, 2015I am facing difficulties in identifying the proper way to add the selected colors of cards into an arraylist. I am having an arraylist which is:
Java Code: private List<String> selectedCars = new ArrayList<String>(); mh_sh_highlight_all('java'); And one more for the carColors:
Java Code: private List<String> carColors = new ArrayList<String>(); mh_sh_highlight_all('java');
The selectedCards array will store the selected cars ['TOYOTA','MAZDA','NISSAN'] as per the selection from the user.For certain types, there is one default color which is 'Black', however for some of them, the user can select different colors.(ex. if selection is 'Toyota')
Java Code:
String carColor="";
String toyotaColor=""; // The value will be retrieved from the form once the user selected the color
if (selectedCars.contains("MAZDA"))
{
carColor="Black";
}
else if (selectedCars.contains("TOYOTA"))
{
carColor=toyotaColor;
[code]....
How To Display Default Constructor Values
Sep 13, 2014I am writing a program that accepts input from the user, I want default values displayed before the input values.
Java Code:
public surfboards() {
surfboardType = "Type not assigned";
shaperName = "Shaper not assigned";
constructionType = "Construction Type not assigned";
surboardSize = 0D;
} mh_sh_highlight_all('java');
I can get the output to display as shown below
(THIS IS WHERE I WANT DEFAULT CONSTRUCTOR DISPLAYED. Currently not displayed)
Type not assigned
Shaper not assigned
Construction Type not assigned
0 Feet
(THIS IS WHERE I WANT DEFAULT CONSTRUCTOR DISPLAYED. Currently not displayed)
input:
Java Code:
Enter Surboard Type:
test
Enter Shaper Name:
test
Enter Surfboard Construction Medium:
test
Enter Surfboard Size:
6.5 mh_sh_highlight_all('java');
Output:
test
test
test
6.5 feet