Final Reference Variables In Java
Feb 28, 2015I am unable to understand the meaning of this sentence "final reference variables must be initialized before the constructor completes.",What is trying to imply?
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Final Static Variables In GregorianCalendar
Oct 27, 2014why using the get method(c.get(c.HOUR_OF_DAY)); gives me the correct hour(currently 19) but directly accesing c.HOUR_OF_DAY returns 11 ? It shows In the documentation that HOUR_OF_DAY is public.
import java.util.*;
public class calendar2 {
public static void main(String[] args) {
new calendar2().timer();
}
private void timer() {
Calendar c=Calendar.getInstance();
//c.clear();
System.out.println(c.get(c.HOUR_OF_DAY));
System.out.println(c.HOUR_OF_DAY);
}
}
Accessing Variables - What Is The Final Value Of Counter
Mar 7, 2015While reading head first java i encountered a problem(Pg. 90 chapter 4 - mixed messages).
Suppose in a class(say A) outside main() a counter variable is declared and initialized to 0.
In main() declared the array of objects of the class A.
Consider a while loop in which we increment the counter as follows:
public class A{
int counter = 0;
public static void main(String[] args){
A[] arr = new A[20];
int x = 0;
while(x<4){
arr[x] = new A(); //arr[] is array object
arr[x].counter += 1;
x++;
}
}
};
what is the final value of counter ? will it be the same for all array objects.
Define All Local Variables And Method Parameters As Final?
May 16, 2015I am using findbugs and PMD as a code analyser. I am keep getting warnings to use local variables and method parameters as final.
I want to know if its a good practice to keep them final or what to do?
Sometime i have a private method which is 1 line longer. Sometime it is annoying to use final.
Creating Final Arrays With Final Elements
Aug 2, 2013I want to create a final array with final elements
{code}
final int[] array = {0, 1, 2, 3, 4, 5};
{code}
But here only the reference of the array is final , not it's elements ... So how can I do that??
Where Are All Keywords Like Final And This Stored In Java
Jan 23, 2014Which package or class i can find all the predefined keywords in java like "this" etc...
actually i want to know if this operator is itself final in nature or not from its syntax?
Java And Passing By Reference
Nov 12, 2014I 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.
Possibility To Use Pass By Reference Technique In Java
Aug 27, 2014if there is a possibility to use the pass by reference technique in java like in C++.URL....
View Replies View RelatedSwing/AWT/SWT :: Getting JFrame Reference Into Java Bean Using RMI?
May 21, 2014I got a project at my university , and we are working with JBoss with the free version WildFly .And also with Java EE.
Now the application is a simple game of Battle Ships or sinking ships to be honest i am not sure as to how the game is actually called.
Registering a user and saving his or her information is not hard using a Stateless java bean , to save the data in the database.
I have a Stateful java bean for every user , the bean is created on the server side after the user succeeds in logging in to the game.
This bean is used mainly for sending an invite from one user to another , to log out the user and everything else that is needed for the user.
The main problem that i encountered here is that JBoss dose not let me have a reference on my frame inside of the bean.
This makes things hard because i would need to use a Timer to ask the bean every second or so if there is an invite from someone , and i would need to save all of the invites .
This was the only thing i could think of .And also implementing the game it self , the communication between users would be complicated more so than i think its needed.
Then my professor said that i could make a service on the clients side in witch i would have a reference of the JFrame , and i could send this service to the java bean and using this service i could get access to the JFrame making things faster.
This would make things a lot easier.For the invite and for the game itself too.
My professor explained that JBoss or WildFly is based on RMI , and he said also that i would need to set up the registry on the server side .But i got lost because i was not sure as to what should i search for .
We are using an older version of WildFly not the newest but one version older , CR1 i think.
And we are also using JPA in the Dynamic web project , server .
Queue Operations In Java - Using Reference As Pointer
May 28, 2014I am trying to run the queue operations in java such as enqueue, dequeue using pointers ... How to use references as pointer in java.
View Replies View RelatedJava-8 :: Method Reference Does Not Work With Decorator Pattern
Mar 28, 2014I 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!
Local Variables In Java
Jan 11, 2014you can also refer this link Local variables in java?Local variables in java?To meet temporary requirements of the programmers some times..we have to create variables inside method or bock or constructor such type of variables are called as Local Variables.
----> Local variables also known as stack variables or automatic variables or temporary variables
----> Local variables will be stored inside Stack.
-----> The local variables will be created while executing the block
in which we declared it and destroyed once the block completed. Hence the scope of local variables is exactly same as the block in which we declared it.
package com.javatask.in;
class A{
public static void main(String args[]){
int i=0; // Local variable
[code]....
Int Variables And Printf In Java
Mar 22, 2014I write the following statement:
int num1 = (int)( 1000 * ( generator.nextFloat() ) );
System.out.printf("%d", num1);
and I get an error!
The weirdest thing is that 'num1' does NOT show in variables window. How can it be?
In Java Can Do Arrays With Variables?
Apr 7, 2014So like, in lua programming language you can do things like,
Array = {1, 2, 3, abc = 5, efg = {123, 456, 789, hij = {"tests","works!"}}, hij = true}
Array[1] = 5
Array[3] = true
Can you do atleast something like this in java or?
I would like to do this because if let's say I was making a game, I could define what tiles are passable and which are not and then their location or something, so like this:
//p (passable) stands for if possible to walk on
//c stands for tile image
t = ["grass.png","water.png","chest.png"]
Tiles = [
[p = false, c = t[1], x = 3, y = -2 ],
[p = true, c = t[0], x = 4, y = 3 ],
[Code] ....
Or something...
Java Applet - Sharing Variables With Another Class
Mar 29, 2015I have An Issue With My Java Applet. Im Trying To Share My Variables With Another Class, But Its Not Working.
Class 1
package com.Tobysmith10.game.main;
import java.applet.Applet;
import java.awt.Graphics;
public class Game extends Applet{
public void init(){
setSize(850,480);
public void paint(Graphics g){
g.fillOval(x,y,20,20);
}
}
Class 2
package com.Tobysmith10.game.main;
import java.applet.Applet;
public class gameLoop extends Applet implements Runnable{
public int x, y;
public void run(){
while(true){
x = 100;
y = 100;
}
}
}
So im sharing the x and y variables with the Class 1 , but I get yellow lines under it and when i run the program, it crashes, how do I get class 1 to recognize the variables from class 2 ?
Java Int Short And Byte Variables Are Same Thing?
Mar 15, 2015okay so it says that java int short and byte variables are the same thing. They take whole numbers. But what is the point of byte and short to even exist if int covers it all? Is the short and byte just for fun?
View Replies View RelatedPreferential Treatment To Order In Which Variables Are Declared In Java
Jun 25, 2014public class Ball {
private int a=show();
int b;
Ball()
{
b=20;
}
public static void main(String args[])throws Exception {
System.out.println(new Ball().a);
}
private int show()
{System.out.println(b);
return b;
}
}
I wanted to know when are the objects created ? when are they initialized? and how is show() getting called without any reference or "this" ?
Why Constructor Cannot Be Final
Oct 27, 2014"A constructor cannot be abstract, static, final, native, or synchronized."
I understand on why it can't be all of the above, except "final".
Why can't we have a final constructor, i understand constructors are not inherited, hence no chance/case of overriding etc. But why is it not allowed at all ?
Final And Static Method?
Feb 7, 2014My teacher has asked me one question that "What is difference between the final method and static method".
View Replies View RelatedWhy Are Final And Abstract Called As Modifiers
Feb 8, 2015I just wanted to know that why are final and abstract called as modifiers ,what is the essence of calling them as modifiers since there are two types of modifiers access modifiers and non-access modifiers so final and abstract come under the second category ,so why are these called as modifiers?
View Replies View RelatedWhen Final Variable Occupy Memory
Sep 23, 2014when final variable occupy memory in java?
View Replies View RelatedHow To Take Runtime Value For Static Final Variable
Jul 28, 2014How can i take run time value for static final variable...my lecturer said first time assignment is possible for declared final variable but in my case it shows compile time error..I'm placing my program below with error message
class Sample
{
static final String cname;
void print() {
System.out.println(cname);
}
public static void main(String args[])
{
cname=args[0];
Sample s=new Sample();
s.print();
}
}
Sample.java:11: cannot assign a value to final variable cname.
cname=args[0];
Grade Input And Final Average
Sep 15, 2014For this assignment you will be writing a grade book program. The program will work for one student. It will need to take as input the students name. The user will then be asked to input grades into three categories in this order:
1) homework;
2) quizzes;
3) tests.
The grades in a given category will be averaged to one number that is the average of all grades in that category. The final average will be the weighted average of each category, where homework is worth 25% quizzes are worth 25%, and test are worth 50%. Like this:
Homework Grades: 65, 70, 75, 80, 80 Homework Average: 74
Quiz Grades: 75, 80, 85, 80. Quiz Average: 80
Test Grades: 75, 80, 85, 75 Test Average: 78.75
Final Average = 0.25*HomeworkAvg + 0.25*QuizAvg + 0.50*TestAvg = 77.87
But i only have the average and i dont know how to move past that..
Heres my average code :
import java.util.Scanner;
public class Homework3 {
public static void main(String[] args) {
Scanner myScanner = new Scanner(System.in);
int gradeCount = 0;
int grades = 0;
int holder = 0;
[Code] .....
What Is The Impact Of Declaring A Method As Final
Nov 14, 20141 Can method declared as final be overridden and overloading ?
2 if A is static sub class of B. how to access a method in class A ?
Parsing Error With Final Bracket
May 8, 2014Im working on a class to add to my final project but im getting a parsing error for the final bracket, i double checked to make sure im not missing any but im still getting an error
import java.util.Scanner;
public class totalprice
{
public static void main(String[] args)
{
scanner keyboard = new Scanner(System.in);
{
DecimalFormat num = new DecimalFormat("#.00");
char meal;
int ammount;
double cost;
[code]....
Final Field Initialization With Exceptions
May 11, 2014consider:
class A {
final Object b;
public A(C c) {
try {
b = c.someMethodThatMayThrowSomeException();
} catch (SomeException e) {
b = null; // This line results in compiler error: "variable b might already have been assigned"
}
} // take away b=null line and you get "variable b might not have been initialized" on this line
}
Why? How could 'b' be assigned if the exception was thrown?
Btw, the workaround is to wrap the method call:
private final Object initB() {
try {
return c.someMethodThatMayThrowSomeException();
} catch (SomeException e) {
return null;
}
}
and use b = initB(); in the constructor. But that seems like it should be unnecessary.