Null Is What Type Of Data Type
Sep 3, 2007method passing null to the called function, compiler would take that parmer as what type of paramer???
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Getting Int Type Cast To Lower Precision Char Type In Parasoft JTEST
Mar 11, 2014Below code I am using to typecast int to char.
char escapeValue = (char)0;
char cha = (char) 10;
escapeValue = (char)(escapeValue * cha); // Here am getting the above error.
I have 38 similar issues in my workspace.
Is Type Irrelevant As Long As Value Is Within Boundaries Of Type Of Switch Expression
Apr 30, 2014If you have final int i = 1;
short s = 1;
switch(s) {
case i: System.out.println(i);
}
it runs fine. Note that the switch expression is of type short (2 bytes) and the case constant is of type int (4 bytes).My question is: Is the type irrelevant as long as the value is within the boundaries of the type of the switch expression?I have the feeling that this is true since:
byte b = 127;
final int i = 127;
switch(b) {
case i: System.out.println(i);
}
This runs fine again, but if I change the literal assigned to i to 128, which is out of range for type byte, then the compiler complains.Is it true that in the first example the short variable and in the second example the byte variable (the switch expressions) are first implicitly converted to an int and then compared with the case constants?
How To Convert Input Array Of Type Strings To Class Type
Aug 14, 2014class Passenger{
String name;
int age;
char gender;
int weight;
public Passenger(){
[Code] ....
This is showing error.....error it gives isthat it cannot change from string type to passenger type......... How to do it??????
Addition Of Generic Type Parameter Causes Member Type Clash
Apr 22, 2014Got a problem with generics, which I'm still pretty new at. Here's a program that compiles fine:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
It's useless, but it compiles. If I change Line 14, however, to add a generic type parameter to the ListHolder class, Line 10 no longer compiles:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
I get this error:
Uncompilable source code - incompatible types: java.lang.Object cannot be converted to javax.swing.JComponent
at experiments.Experiments.main(Experiments.java:10)
Apparently, the introduction of the type parameter leaves the compiler thinking that aList is of type Object. I can cast it, like this:
JComponent c = ((ArrayList<JComponent>)holder.aList).iterator().next();
That makes the compiler happy, but why is it necessary? How does adding the (unused) type parameter to the ListHolder class end up making the compiler think the aList member of an instance of ListHolder is of type Object?
How To Convert String Type To Generic Class Type
Mar 22, 2015I have a String repersentaion of some Object.I want that object convert back into some class type how can I do this?
View Replies View RelatedHow To Convert ZipEntry Type To File Type
Dec 4, 2014I'm trying to parse and compare the content of a zip file. However I'm stuck at what SHOULD be a very simple problem, however I can't seem to find a solution. I have done the following:
ZipInputStream zin1 = new ZipInputStream(fin);
ZipEntry ze1 = null;
fin2 = new FileInputStream(fileName2);
ZipInputStream zin2 = new ZipInputStream(fin2);
ZipEntry ze2 = null;
//fin.close();
ze1 = zin1.getNextEntry();
ze2 = zin2.getNextEntry();
Which gives me the first entry of each zipfile as a ZipEntry type object. I have tried getting the path of the file (inside the zip file) and using this to create a File type object. This does not seem to work though I get:
Exception in thread "main" java.io.FileNotFoundException: My DocumentsmetadatacoreProperties.xml (The system cannot find the file specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileReader.<init>(Unknown Source)
And this is because I get a null return from trying to create the File file1 = new File(correctLocation);
I guess I cannot access the file inside a zip file this way. So my question is how can I make a ZipEntry type object into a File type object?
Data Type That Can Store Methods
Mar 21, 2015I was wondering is there any data type that can store method?
View Replies View RelatedUsing Boolean Data Type In Program
Sep 25, 2014While practicing java i have came across boolean data type. i have executed below program but i am not sure how i got output of the program like below:
10 > 9 is true
Here is my program:
class BoolTest3
{
public static void main(String args[])
{
System.out.println("10 > 9 is "+(10>9));
}
}
My question is: how this program will come to know that 10>9 true or false.. how bolean data type used in this program.
Type Of Expression Must Be Array Type
Dec 30, 2014The objective of the code is to add new records based on existing records with a partial change to the key. I'm getting "type of the expression must be an array type but it resolved to DstidArray" on dsTidRecTbl[i]
String stMajor = request.getParameter("stMajorVersion");
String stMinor = request.getParameter("stMinorVersion");
String stPatch = request.getParameter("stPatchVersion");
StringBuffer stKeySB = new StringBuffer(stMajor+stMinor+stPatch);
String stKey = new String(stKeySB.toString());
DstidArray dsTidRecTbl = new DstidArray(stKey);
request.setAttribute("dsTidRecTbl", dsTidRecTbl);
[code]....
Creating Array With Multiple Data Type?
Oct 10, 2014i need to create an array with attributes name, gender, phone, age.and then sort acording to age in ascending order.
i created like this,
public class Array{
private String[] name={"ram", "katy", "priti", "john"};
private String[] gender={"male","female","female","male"};
private int[] phone={989898089,89898989,8982989089,898908989};
private int[] age={45,24,30,28};
public void printarray(){
[code]....
This code sorts the age attribute alone and when printing ouput it swaps one person's age to other person, how to make it correct
Passing Primitive Data Type Arguments
Jun 5, 2014I am totally new to Java. What is the purpose of this method?
Flow of the int x=3; like where does the 3 go step by step?
Passing Primitive Data Type Arguments (from oracle java tutorials)
Primitive arguments, such as an int or a double, are passed into methods by value. This means that any changes to the values of the parameters exist only within the scope of the method. When the method returns, the parameters are gone and any changes to them are lost. Here is an example:
public class PassPrimitiveByValue {
public static void main(String[] args) {
int x = 3;
// invoke passMethod() with
// x as argument
passMethod(x);
[Code] ....
Double Data Type Outputting To Exponent?
Nov 9, 2014I was struggling to use BufferedReader to extract some data and then perform some calculations and then have the results as outputs.
I haven't quite solved that issue but in order to progress, I hard coded some values into my application and proceeded with the actual calculation loops etc.
Currently, the value out put from one of my calculations is given as:
1.1704926E7
How can I make the console show it in a natural way. I've performed the calculation manually and it should be 11704926.5 I don't want to lose that .5!
Passing Reference Data Type Arguments
Oct 21, 2012Primitive arguments, such as an int or a double, are passed into methods by value. This means that any changes to the values of the parameters exist only within the scope of the method. When the method returns, the parameters are gone and any changes to them are lost.
Reference data type parameters, such as objects, are also passed into methods by value. This means that when the method returns, the passed-in reference still references the same object as before. However, the values of the object's fields can be changed in the method, if they have the proper access level.For example, consider a method in an arbitrary class that moves Circle objects:
public void moveCircle(Circle circle, int deltaX, int deltaY) {
// code to move origin of
// circle to x+deltaX, y+deltaY
circle.setX(circle.getX() + deltaX);
circle.setY(circle.getY() + deltaY);
// code to assign a new
// reference to circle
circle = new Circle(0, 0);
}
Let the method be invoked with these arguments: moveCircle(myCircle, 23, 56)
Inside the method, circle initially refers to myCircle. The method changes the x and y coordinates of the object that circle references (i.e., myCircle) by 23 and 56, respectively. These changes will persist when the method returns. Then circle is assigned a reference to a new Circle object with x = y = 0. This reassignment has no permanence, however, because the reference was passed in by value and cannot change. Within the method, the object pointed to by circle has changed, but, when the method returns, myCircle still references the same Circle object as before the method was called.
Unable To Use Double Data Type In For Loop
Aug 12, 2014I am trying to use double data type in a for loop for precise operations and just to see if there could be any problem doing that I tested a small code :
public class doubleLimit {
public static void main(String[] args){
for(double i=-0.1;i<=0;i+=0.01)
System.out.println(i); }}
The output I was expecting is :
-0.1
-0.09
-0.08
-0.07
-0.06
-0.05
-0.04
-0.03
-0.02
-0.01
0.00
But the output of the code is :
-0.1
-0.09000000000000001
-0.08000000000000002
-0.07000000000000002
-0.06000000000000002
-0.05000000000000002
-0.040000000000000015
-0.030000000000000013
-0.02000000000000001
-0.01000000000000001
-1.0408340855860843E-17
Why is the code not working the way I expected, I think it has something to do with any property of double but I am not sure.
Adding Any Type Of Data To A Generic List?
Aug 28, 2014Is this the proper way to add to a generic list? My code works just fine, but I got this feeling that there might be some kind of flaw in it or something. Is this pretty much the basic way to add any type of data to a generic list?
import java.util.LinkedList;
public class ListOfGeneric<E> {
private LinkedList<E> myList;
ListOfGeneric(){
myList = new LinkedList<E>();
[Code] ....
Store Data From A File Into Array Of Type Product?
Mar 17, 2015public class InputFileData {
/**
* @param inputFile a file giving the data for an electronic
* equipment supplier’s product range
* @return an array of product details
* @throws IOException
*/
public static Product [] readProductDataFile(File inputFile)
throws IOException{
// YOUR CODE HERE
}
This code is meant to be used to read a text file and store the data in an array of type Product[]. I know how to read in a text file and have it sort it into an array, but I've never seen code laid out in this fashion before (specifically "public static Product[]", and I'm unsure how to work with "(File inputfile)". I've looked all over the place but can't find any examples of anything like this.
Also, the code given cannot be changed, as it's that code I have to work with.
I still don't understand how to use it as a whole. For example, do I read the file in the main and have this method read that in and output to the Product class? Do I read the file in this method? I can't work out how to make this work when I have to use this method.
How To Get Date Data Type From MySQL To Java Format
May 22, 2012In my project i am facing an problem, The My SQL Data base will accept the date format of yyyy/mm/dd only as "Date" data type but in my program i wants to use dd/mm/yyyy format. (i have this same format now) that's why I am unable to insert / retrieve it..
View Replies View RelatedJava Generics - Why Cannot Use Primitive Data Type Like Int / Double
Feb 21, 2014I have doubt in generics,
List<int> c=new ArrayList<int>();
why we cannot use primitive data type like int,double.
JDBC :: How To Determine DATE Data Type Of Parameter If It Is Not Specified
Feb 2, 2015Oracle JDBC driver determine the DATE data type of parameter correctly without any typecasting.
Example:
ps = conn.prepareStatement("SELECT ? FROM DUAL");
ps.setObject(1, Date.valueOf("2014-01-11")) ;
I have tried the same example with other database driver but it gives error.
PostgreSQL JDBC driver:
org.postgresql.util.PSQLException: ERROR: could not determine data type of parameter $1
ps = conn.prepareStatement("SELECT ?");
ps.setObject(4, Date.valueOf("2005-01-01"));
so I want to know how Oracle JDBC driver determine the DATE data type of parameter.
JDBC :: Determine DATE Data Type Parameter If It Is Not Specified?
Feb 2, 2015Oracle JDBC driver determine the DATE data type of parameter correctly without any typecasting.
Example:
ps = conn.prepareStatement("SELECT ? FROM DUAL");
ps.setObject(1, Date.valueOf("2014-01-11"));
How Oracle JDBC driver determine the DATE data type of parameter.
Display Month Using Enumerated Data Type From String Variable
Apr 1, 2014I have created an enumerated data type that represents months. In my program I have asked the user for the month. I hold the month entered by user into a string variable. From that string variable I'm trying to display the month using my enumerated data type. I know I can use if statements, but is there another simple way to do it?
import java.util.Scanner;
public class demo {
//Enum class called month that has constants in it representing months
enum month{january,february,march,april,may,june, july,august,september,
october,november, december};
[Code] ....
Implement A Set Abstract Data Type Using Singly Linked Lists
May 6, 2015I am trying to implement product method below which returns the set representing the Cartesian product of the current set and a given set (the Cartesian product contains all ordered pairs (a, b) where a belongs to the current set, and b belongs to the given set). The product should be a ListSet <Tuple<E>> object where each ordered pair is a Tuple element. (I have a Tuple class which implements an ordered tuple)
What am I trying to do in the product method : Make 2 for loop and inside the for loop make an array of <E> then set the 2 elements of the tuple then again set tuple and add it to arrayList. how to set 2 elements of the tuple and set tuple ??
public class ListSet<E> implements Iterable<E>{
SinglyLinkedList<E> sl;
public ListSet(){
sl = new SinglyLinkedList<E>();
[code]....
Creating New Data Type VeryLargeInteger With / Without Premade Java Classes
Jan 22, 2014What I'm doing about it: googling the shit out of my problems, consulting you fine readers, consulting my friends, and yesterday I signed up for Lynda.com. I'm hoping 30hrs+ or so of watching, rewatching, and analyzing the example code will catch me up before I get too behind in CS302
** Assignment Prompt **
Integer types are very convenient, but their limited width and precision makes them unsuitable for some applications where precision is more important than speed. Develop a class VeryLargeInteger that can handle arbitrary long integer numbers (both negative and positive) and the basic arith- metic operations (addition, subtraction, multiplication, division, and remainder).
Hint: The number could be represented as string, the sign could be represented either as boolean or as part of the string.
Note: Implementations of addition/subtraction through repeated use of a constant incremen- t/decrement will not be accepted. Implementations of multiplication and division that rely only on addition and subtraction will not be accepted.
I know I'm going to have to create a separate tester to call on the VeryLargeInteger class and it's math methods. For the new data type, should I convert the integer/string into an array in order to handle the large length of the number? I know he wants us to use recursion for the math methods. My gut tells me addition and subtraction will be slightly easier than multiplication and division. I know I'll have to reference the other methods for division. We aren't allowed to use the BigInteger class.
How I should construct any of the methods.
Java Code:
import java.util.ArrayList;
/**
∗ VeryLargeInteger (VLI) is a class for arbitrary precision integer computation
*/
public class VeryLargeInteger {
private int[] num1;
private int[] num2;
private int[] num3;
[code]....
JSP :: Get Double Data Type In Order To Display In The View Through Servlet
Dec 16, 2014How to get a double data type in order to display in the view through a servlet:
objReferencias.setImprevistos(request.("imprevistos"));
Question:
request.getDouble("imprevistos));? or
request.getDoubleParameter("imprevistos));?
I've been searching but I have not found the appropriate answer.
Error In Program To Read Int Or Float Type Data From Keyboard
Aug 9, 2014Here is a code and error .....
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