Local Variable Not Initialized
Jun 19, 2014
I am reading input from a file that has following information:
line 1 = numbers of integers in array,
line 2 = elements in array1,
line 3 = elements in array2.
These lines constitute a test case. There are 1000 test cases in the input file.
So basically, I read the length of arrays, populate the arrays by reading from the file.
The code is below ( I have not included reading input code):
while(test_case<1000){
if (count == 1){ //count keeps track of lines in input file
vec_length = Integer.parseInt (tokenizer.nextToken());
count++;
continue;
}
if (count == 2){ //populates array1
vector1 = new int[vec_length];
for (int i = 0; i < vector1.length; i++)
vector1[i] = Integer.parseInt (tokenizer.nextToken());
count++;
continue;
}
Array2 is populated using the same as above code. However when I use the following code:
for (int i=0; i<vec_length; i++)
temp += vector1[i]*vector2[i];
I get " local variable vector1 and vector2 have not been initialized error". But both arrays have been initialized in the if{} block. Is it because initialization was local to if block?
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May 13, 2014
public class Apples{
public static void main (String args[]){
int array[]={21,16,86,21,3};
int sum=0;
int average;
[Code] .....
Eclipse: Exception in thread "main" java.lang.Error: Unresolved compilation problem:
The local variable average may not have been initialized
at Apples.main(Apples.java:11)
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Oct 27, 2014
The term "Local variable" is related to scope. That is a local variable is one which is defined in a certain block of code, and its scope is confined inside that block of code.And a "Member variable" is simple an instance variable.
I read in a discussion forum that when local variables are declared (example code below), their name reservation takes place in memory but they are not automatically initialized to anything. On the other hand, when member variables are declared, they are automatically initialized to null by default.
Java Code: public void myFunction () {
int [] myInt; // A local, member variable (because "static" keyword is not there) declared
} mh_sh_highlight_all('java');
So it seems that they are comparing local variables and member variables. While I think a member variable can also be be local in a block of code, isn't it?
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Feb 21, 2015
I know what the error means but I don't think initializing the variable will make my code work as intended so I'm having a little dilemna here... here's the code and I'll highlight the part that is said to be not initialized:
Java Code:
import java.util.Scanner;
public class ItemCost {
public static void main (String []args){
int i=1,item=1,e=1, f=1, g=1;
int items, d ;
double gst, qst, subt, Tot = 1, PriceItems ;
[Code] ....
So I'm supposed to get the following output :
Java Code:
Please input the amount of items bought 2
Please input the price of the item 1 1
Please input the price of the item 2 2
Please input the rate of GST in % 20
Please input the rate of QST in % 18 mh_sh_highlight_all('java');
HOWEVER my program doesn't seem to add input of item 1, and 2 if I initialize subt= 0 initially. It'll only take the last value inputted in the loop. By the way, the increments are counters to count the amount of errors the user might input by accident ( or whatever). Some people have been pointing it out as useless but that's the only way I found it to work.
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Nov 12, 2014
In 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
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Mar 31, 2014
Consider the following simple code:
public class Test {
private final int arg;
private final Runnable runnable1 = new Runnable() {
@Override
public void run() {
// No errors here, exactly as expected
System.out.println("ARG: " + arg);
[Code] ....
The java compiler (version 1.8.0-b132) produces the following error when compiling this code:
"Error:(14, 46) java: variable arg might not have been initialized"
Actually, I do not expect the error here.
Both declarations 'runnable1' and 'runnable2' are essentially the same: these are just Runnable objects accessing value of the 'arg' field (which is initialized in the constructor).
The only difference between the declarations is that 'runnable1' - is an old-fashion instantiation of Runnable, whereas 'runnable2' - is an instantiation of Runnable via a lambda expression.
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Feb 28, 2015
I want to use a try catch block, but I am not sure how to fix this problem:
int a;
try{
a = Integer.parseInt(A.getText());
}
catch (Exception e){
Output1.setText("Error");
}
//do someting with a here
The purpose of the try-catch is to catch blank input.The problem with this is that underneath the try - catch I get an error saying that the variable might not have been initialized. I know why this happens. I know I could initialize the varaible before the try - catch, but there is no default or null I can set an int as. If I initialized it as 0, the blank input will no longer be catched.how to make this problem disappear?
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Aug 26, 2014
I'm making a program that can read an input of English or Morse code and return an output of Morse code or English back. The English-->Morse works fine, but not Morse-->English. I'm pretty sure my solution lies in displaying the variable 'morseWord', but no matter where I put it, I always get an error saying the variable has not been initialized. Here's what it looks like now:
import java.util.Scanner;
public class pro1
{
static final String[] alpha = {"a", "b", "c", "d", "e", "f", "g", "h", "i",
"j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u",
"v", "w", "x", "y", "z", " "};
static final String[] morse = {".-", "-...", "-.-/>/>.", "-..", ".", "..-.", "--.", "....", "..",
".---", "-.-/>/>", ".-..", "--", "-.", "---", ".--.", "--.-/>/>", ".-.", "...", "-", "..-",
"...-" ,".--" ,"-..-", "-.-/>/>-", "--..", " | "};
[Code] .....
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May 12, 2015
As a studyproject I'm currently writing a class the allows me to get al fun dates (like when eastern is in a given year, what day a given date has, calculate the date of tomorrow).
While working on the following method:
public String getNextDate (int day, int month, int year) {
String nextDate;
int nextDay = getNextDay(day, month, year);
int nextMonth = getNextMonth (day, month, year);
int nextYear = getNextYear (day, month, year);
return nextDate = "the day after " + month +"-" + day + "-" + year + " is " +
nextMonth + "-" + nextDay + "-" + nextYear + ".";
}
I get a notion in my lovely IDE (eclipse) reminding me I'm not using nextDate ("The value of the local variable nextDate is not used"). But I feel I really do use nextDay here. So either I'm making a coding(style) mistake giving me this notion or I should just ignore this notion.
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Feb 3, 2014
Here, I have just tried out to take a value from the database and storing it into local variable then I want to have that value in the value attribute of <input> tag but somehow, I can't get it..
Here, below is my code..
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "[URL]....">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
[Code]...
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Sep 30, 2014
I have a question regarding best practice in using local variables as my method return variable. I have a method like this:
myReturnObject getMyObject(String input) {
myReturnObject myObject = null;
try {
myObject = helperObject.someOtherMethod().getObject(input); //getObject has return type myReturnObject
} catch (Exception e) {
//log any problems
}
return myObject;
}
And I'm wondering if I rewrite like this if I'll see some performance optimization benefit:
myReturnObject getMyObject(String input) {
try {
return helperObject.someOtherMethod().getObject(input); //getObject has return type myReturnObject
} catch (Exception e) {
//log any problems
}
return null;
}
myObject can be quite large -- so I'm wondering if I can omit the myReturnObject local variable instance if it'll save some work from the garbage collector.
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Sep 23, 2014
I continuously get an error for lines 34, 36, and 37 saying that the variables may not have been initialized.
import java.util.Scanner;
import java.util.Random;
public class MathTutor {
public static void main(String[] args) {
Random r = new Random ();
Scanner input = new Scanner (System.in);
/*int min=1;
int max=10;*/
int num1,num2,operation;
int n1= r.nextInt((9+1)+1);
int n2= r.nextInt((9+1)+1);
operation= r.nextInt(3);
int correctAnswer;
int userAnswer;
[code]....
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Apr 3, 2014
How to use initialized applet class?
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Sep 18, 2014
class Super { static String ID = "QBANK"; }
class Sub extends Super{
static { System.out.print("In Sub"); }
} public class Test{
public static void main(String[] args){
System.out.println(Sub.ID);
}
}
According to me output should be "QBANK" In Sub...BECAUSE sub default constructor will call super() constructor.. below is the definition in jls which i am unable to understand ....
A class or interface type T will be initialized at its first active use, which occurs if:
T is a class and a method actually declared in T (rather than inherited from a superclass) is invoked.
T is a class and a constructor for class T is invoked, or T1 is an array with element type T, and an array of type T1 is created.
A non-constant field declared in T (rather than inherited from a superclass or superinterface) is used or assigned. A constant field is one that is (explicitly or implicitly) both final and static, and that is initialized with the value of a compile-time constant expression . Java specifies that a reference to a constant field must be resolved at compile time to a copy of the compile-time constant value, so uses of such a field are never active uses.
All other uses of a type are passive. A reference to a field is an active use of only the class or interface that actually declares it, even though it might be referred to through the name of a subclass, a subinterface, or a class that implements an interface.
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Jun 9, 2014
I have a field that initializes a Calendar object:
Java Code:
private Calendar zeroPointTime = zeroPointTime();
private Calendar zeroPointTime(){
int year = 2000;
int month = 0;
int date = 1;
int hourOfDay = 0;
int minute = 0;
Calendar calendarTime = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
calendarTime.set(year, month, date, hourOfDay, minute);
[Code] ....
But other times I need to reference what the value was initialized with, not offset values added to it with various function calls.
When I use add() will that modify zeroPointTime? If so, how can I add seconds to a Calendar object without altering its value?
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Oct 10, 2014
Take a look at this screenshot... my java integrated devlopment envirnment is telling me I have a null pointer on a line with three variables ALL which were initialized.
I thought a null pointer was called when a variable doesn't get initialized.
Edit: Here is the java file and resources being used: [URL]
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Nov 14, 2014
class GVector {
// TODO: declare a private array to save the vector coordinates
// Creates a mathematical vector of d dimensions, initialized at 0
public GVector(int d) {
// TODO: implementation
[Code] ....
I'm confused with what type of array I need to use to save the vector coordinates and what to put in Gvector. Is it a constructor?
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Feb 23, 2014
i have this following codes and im trying to make a java program that calls an object value initialized.
public class TestClass
{
public String name;
public int age;
public void myMessage()
{
System.out.println("Hello I'm" + name + "and i'm" + age + "years old");
}
}
what i want is to put the following codes of the object.. so once i compile and run the project it executes the value of an object from the method i defined above.
TestClass myName = new TestClass();
myName.name = "Jefferson";
myName.age = 18;
my question is, it is possible to declare or define it in the same project? or i need to do this separately?
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Mar 25, 2006
I have a traffic simulation code that is producing a start:applet not initialized error each time i run it. This is the code
import java.io.InputStream;
import java.net.URL;
import java.util.*;
import java.awt.*;
import java.applet.Applet;
import java.lang.Thread;
class Node {
[Code] ....
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Mar 8, 2014
again i am facing problem i am able to run Listener class also the ContextListener is initialised but it is giving me error on Tomcat 6.0 command prompt
Here is my Listener Class Sample.java i am able to compile the code but it is giving java.lang.nullpointer exception at runtime on Tomcat.exe Is there is problem in my code
package servlet;
import java.io.*;
import java.io.FileInputStream;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;
import javax.mail.internet.MimeMessage.*;
import javax.mail.internet.InternetAddress.*;
import java.util.*;
[Code]...
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Jan 11, 2014
you 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]....
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Jun 22, 2014
is it necessary that inner classes inside a static method be static . If yes Why?
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Aug 1, 2014
I edited some lines from "[URL] ...." and saved it as html file; now if a friend want to do a search in Wikipedia for cats, the edited page should show up instead of original page.Is there a way to do this using java script.
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Feb 18, 2015
Below is my ejb-jar.xml
<!DOCTYPE ejb-jar PUBLIC '-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN' 'http://java.sun.com/dtd/ejb-jar_2_0.dtd'>
<ejb-jar>
<display-name>TestEJB</display-name>
<enterprise-beans>
<session>
<ejb-name>TestSessionLocal</ejb-name>
[code]....
All my classes implement proper local classes EJBLocalHome and EJBLocalObject.This configuration used to work fine in JBOSS 5.1.0 G
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Jan 31, 2014
how I can configure an applet to get access to local resources such as file system, browser, etc.
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May 23, 2014
Let's say I have a loop that loops through objects in an ArrayList then does stuff with them. Is it better for me to store the object in a temporary local variable and do stuff with it, or always use the ".get(arrayindex)" thing?
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