I tried the following and it gives me null pointer exception. I just want to verify if what is the actual value of a length of an array?
Object [] obj = null;
System.out.println("length:" + obj.length);
I am working on an assignment covering exception handling and am stuck on part of the assignment. How can you test for array length = 0?
When I try something like: if (array.length == 0) on a null array, naturally I get a NullPointerException. I would try something like if (array != null) but both array length of 0 and null array are supposed to throw different expressions.
how you can do array.length, I have an array with [][][][], and what do I do to find the length of one section?
So let's say
Java Code: int array[][] = {
{5, 5, 5, 5},
{4, 4, 4, 4},
{3, 3, 3, 3}
} mh_sh_highlight_all('java');
How do I find out the length of the {5, 5, 5, 5} which is 4. Because there are 4 place-holders.Is there a way?
I have a class of Date with a constructor with 3 parameters in it. Those 3 parameters are int data type just to enter month, year, day.
I have another class called Author which has a constructor of Date diedDate; as a parameter passing to the Author constructor.
I was asked to call the Date parameter is null, call the default constructor but I thought for the Date parameter I could only enter something like 0,0,0 instead of typing in null, null, null because null is for String data type isn't it?
I was inquiring about selecting random numbers from a Fibonacci array, the original post for which is here: Exiting a 'for' Loop Early. I have managed to achieve this with the following code:
System.out.println("Random numbers from the Fibonacci array");
for(int i = 0; i < limit; i++) //Limit is an 'int' of 15 & is set as the length of the Fib. array. I'm calling it for the Random array, too!!
{
Random dice = new Random();
int randomIndex = dice.nextInt(array.length); //The Fib. array was simply called 'array'!!
if (array[randomIndex] < 100)
{
System.out.print(array[randomIndex]+ " ");
}
}
When the code prints I get a random set of numbers which occur in the Fibonacci sequence preceding it. However, the actual length of this Random array also changes each time, and never more than the limit of 15 specified in the 'for' loop. What I want to try and do is print the Random array with a specific length each time. I've tried changing the conditional statement of the 'for' loop in different ways to set the Random array's length, but had no luck.
I've been assigned to create a Black Jack game with a gui. In this game I've created a seperate Player and Dealer class, and both initiated them, however when I try to call a Player object in a certain way I get a null pointer reference. (It should be noted that the Player object is an array)
public void runGame(){
while(running){
while(dealer.getPoints() <=19){
int count=0;
[Code] .....
And this is how I've initilized the Player class in the constructor
Player[] players = new Player[numberofplayers];
for(int i=0; i<numberofplayers; i++){
players[i] = new Player(i);
players[i].setDeck(d1);
gui.add(players[i].getPanel());
}
What I don't get is if I change players[i] to dealer, it works fine.
I am trying to parse a XML string into `org.w3c.dom.Document` object.
I have looked at solutions provided [here](xml - How to convert String to DOM Document object in java? - Stack Overflow), [here](How to create a XML object from String in Java? - Stack Overflow) and a few other blogs that give a variation of the same solution. But the `Document` object's #Document variable is always null and nothing gets parsed.
Here is the XML
XMLMappingValidator v = new XMLMappingValidator("<?xml version="1.0" encoding="utf-8"?>
" +
"<mapping>
" +
"<container>
" +
"<source-container>c:stem.csv</source-container>
[Code] ....
When I call
**v.getXML().toString()**
I get
`[#document: null]`
Clearly, the parse is failing. But I don't understand why.
I created the WSDL first in RSA and then created the java bean skelaton from the WSDL. There are a couple of dateTime fields in the WSDL that are created as GregorianCalendar objects.
When I test with SOAPui and the date fields are passed correctly, everything works great. But when there is an invalid date format or anything else in the SOAP request, instead of returning a Conversion exception or some other validation exception, the field is passed as a null to the request object in the SOAP IMPL. Should't this return an exception?
Sample requests inputs:
<endTimeStamp>2014-01-28T01:30:14.474Z</endTimeStamp> - Date
<endTimeStamp>06-FEB-14 01.51.00.000000000 AM</endTimeStamp> - Null
<endTimeStamp>Any other string be it a date or not.</endTimeStamp> - Null
[Code].....
I am trying to parse a XML string into `org.w3c.dom.Document` object.
I have looked at solutions provided [here](xml - How to convert String to DOM Document object in java? - Stack Overflow), [here](How to create a XML object from String in Java? - Stack Overflow) and a few other blogs that give a variation of the same solution. But the `Document` object's #Document variable is always null and nothing gets parsed.
Here is the XML
Java Code:
XMLMappingValidator v = new XMLMappingValidator("<?xml version="1.0" encoding="utf-8"?>
" +
"<mapping>
" +
"<container>
" +
"<source-container>c:stem.csv</source-container>
[Code] .....
When I call Java Code: **v.getXML().toString()** mh_sh_highlight_all('java');
I get Java Code: `[#document: null]` mh_sh_highlight_all('java');
Clearly, the parse is failing. But I don't understand why.
I have an encoder that will shift the character of a string X places. Im trying to account for the possibility of the shift being larger than alphabet array length. I've come up with the following, but I still get an ArrayIndexOutOfBounds Error and it never gets past the if statement.
private String encryption(char charArrayElement) {
String [] alphabet = {"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"};
String str = String.valueOf(charArrayElement);
[Code] ....
The question pretty much says it all, but I tasked myself with creating a program about lemurs. There are multiple class files in this program. In the below code snippet, I have my TreeLemur.class which extends to the Lemur.class which extends to the Mammal.class. However, when I create a Tree Lemur object in the main program, it is returning null consistently from certain methods. What am I doing wrong here?
TreeLemur.class :
public class TreeLemur extends Lemur {
private String groupSize;
private String diet;
private String fur;
public void setGroupSize() {
groupSize = "
Group Size: Large";
}
[Code]...
As of yet, I'm just trying to get Tree Lemur working properly to continue with creating the other if-branches within the main program.
Is there a better way to remove null values from an array than what I have tried? This works just fine, but I just get the feeling that there is a better way to do this, without using the JCF.
private static String[] removeNullValues(String[] list){
int count = 0;
for(int i = 0; i < list.length; i++){
if(list[i] == null)
count++;
[Code] ....
I technically dont need to remove the null values for the project that I'm working on (since I just print it out and I can avoid null values with a simple statement like
if(update[i] != null) SOP(update[i])
),
but I'm just curious.
B is an array Object, as you can see if an element is null or not?
View Replies View RelatedIf I set a Jlist to contain an array of objects, how can I display properties of each object instead of the object array list itself. Ex:
Instead of:
Person1
Person2
Person3
display values such as each person name within the Jlist:
Mike
Paul
Andrew
I am trying to return an array and I keep getting a null error. The below class sets the material numbers into an array and should return that array if called :
public class Jobs {
private int[] materialsNumber;
//change to parts and create another class that gets the materials for the parts
public int[] job1() {
materialsNumber[0] = 11960120;
[Code] ....
I later try to call the method. The program executes but stops after I println "test in loop"
public class PurchaseOrdersToParts {
private Jobs job = new Jobs();
int[] getPartsForPurchaseOrder(BigDecimal purchaseOrder) {
System.out.println("inside getparts");
BigDecimal testNum = new BigDecimal(123.0);
[Code] ....
This is the method that is calling the method in the GenerateOrdersToParts class
private PurchaseOrdersToParts purchaseOrdersToParts = new PurchaseOrdersToParts();
@Inject
PoRepository poRepository;
public GenerateShopJobTickets() {
[Code] .....
I'm working on a program to create a blackjack game using objects (one for card, deck. and hand). Withing my hand object I am trying to add cards to the hand but it is only adding the last card i try to add and giving null values for the the ones before.
class BlackJackHand {
private BlackJackCard [] hand;
public void addToHand(BlackJackCard c) {
if (hand == null) {
BlackJackCard [] tempHand = new BlackJackCard[1];
tempHand[0] = c;
hand = tempHand;
[Code] ....
What I want this section to do is add cards to the current hand. I was intending for it the hand to be null at first and the if(hand == null) piece to add the card the first time and then the else piece would be used when the hand already has at leas one card. I want the else section to create a temporary array that is one larger than my current hand, copy the cards from the old hand to the new hand, and then add a new card to the last space before rewriting the old hand as what the temporary hand is.
The code I am using to test if the addToHand() is working is
class BlackJackTest
{
public static void main (String[]args) {
BlackJackCard c1= new BlackJackCard(1,0);
BlackJackCard c2= new BlackJackCard(1,4);
BlackJackCard c3= new BlackJackCard(1,5);
BlackJackHand h1 = new BlackJackHand();
[Code] .....
BlackJackCard has the parameters (int suit, int value)
This should print:
ace of clubs
4 of clubs
5 of clubs
but instead prints:
null
null
5 of clubs
I have a file which contains certain positions ([a][b]) that require to be placed in a certain multi-dimensional array. For example I might have an array String[][] that is a size of 6x6 but only have values in positions [2][1] and [3][2]. Because it is important for me to maintain the given array size and also do certain actions with the given positions I cannot modify the size. In addition I need to count the surrounding neighbors each element has (including elements that are null). However because some of my further code cant process with null elements I need to remove all null elements with " " (blank).
I am not sure how this is done or if it's even possible. If it is not possible how can I do something as close as possible to my needs?
I'm trying write a Dijkstra's implementation in java. First off, here is the algorithm:
package lab3;
import java.util.HashMap;
import java.util.Stack;
/**
* Compute shortest paths in a graph.
*
* Your constructor should compute the actual shortest paths and maintain all the information needed to reconstruct them. The returnPath() function should use this information to return the appropriate path of edge ID's from the start to the given end.
*
* Note that the start and end ID's should be mapped to vertices using the graph's get() function.
*/
class ShortestPaths {
Multigraph graph;
final int INF = Integer.MAX_VALUE;
PriorityQueue<Integer> Q;
[Code] ....
I followed someone else psuedocode very closely but for whatever reason, my edge[] array is just full of null data, which means I can't actually return the shortest path. Why that's happening/how to fix it? Maybe I'm not understanding dijstra's correctly.
I've a vertical-bar-delimited file where most elements contain text, some contain whitespace, and some are empty. Examples:
62RG|fe|Pencil Financial Group, LLC||doug@pencil.com|||85637889|Cross, Ben|bcross@godaddy.net|Bernard|Cross|Ben||315 One Tree Hill Terrace|Lafayette|LA
62RG|fe|Pencil Financial Group, LLC||tracy@pencil.com|||13658734|Dustin Cardwright|dcart@motorola.com|Dustin|Cartwright|||| |LA
which I parse and store with
String str_arry = innline.split( "|", 17);
lisst.add( new Contact( str_arry));
and my Contact class has the constructor
public Contact( String[] str_arry) {
for( int ii = 0 ; ii < str_arry.length ; ii++ ) {
if( str_arry[ii].matches("^s+$")) {
str_arry[ii] = null;
System.out.println("hit a null");
[Code]...
I expect the for-loop in the constructor to find any elements containing whitespace characters and set them to null for subsequent assignment.And when the code runs I do see some hit-statements pop up, so the detecting part is working.
But when I then process the list and access a Contact object and test fields for nulls I don't find any ie
if( aContactObj.getfFCity() == null) System.out.println("city is null");
never prints when it should.
What's the trick? Or is my approach wrong and if so what should it be?
Question 1: I am working on an assignment where I have to remove an item from a String array (see code below). When I try to remove an item after entering it I get the following error "java.lang.NullPointerException." I am not sure how to correct this error.
Question 2: In addition, I am having trouble figuring out how to count the number of occurrences of each string in the array and print the counts. I've been looking at other posts but they are more advanced and I have not yet learned how to use some of the tools they are referring to.
private void removeFlower(String flowerPack[]) {
// TODO: Remove a flower that is specified by the user
Scanner input=new Scanner(System.in);
System.out.println();
System.out.println("Please enter the name of the flower you would like to remove:
[Code] ....
I'm getting an error on line 137 and all it is rsmd = rs.getMetaData();The error happens only after I press a JButton and it is
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerExceptionat softwareDesign.createAccount.actionPerformed(createAccount.java:137)
There is a lot more to it but that has nothing to do with my code it's just the stuff with Eclipse anyway I want to know how do I fix this problem?
public class Test {
public static void main(String[] args) {
Car c = new Car();
c.setInf("toyota", "red");
System.out.println("name: "+ c.brand + " colour: " + c.colour);
[code]....
Why do I get the result brand null, colour null? I know what null means but what am I missing here?
I need to add an employee object that my program has created and put it in a array list. My employee object is first name, last name, and a generated id. I am trying to add a new employee object to an array like this:
public static Employee addEmployees(String first,String last) //this method is in my employee class
{
Employee employee = new Employee(firstName,lastName);
employee.setFirstName(firstName);
employee.setLastName(lastName);
employee.getId();
employeefile.addEntry(employee); //add employee object to array list
[code]...
how to println it to test, but I can't seem to do that or know which class to put this function in. I know about for loops and such, just don't know how to implement it or where.
this is part of a larger project but i figure if i can figure out this first step i can work the rest. I need to get a title from the user add it to a object array (i think thats what it is) and then when i call listAllItems(), items[] should be copied into a string array called listAllItems, and then printed, but currently im jusst having trouble i think making it an object and then make it an item in the items[], if i run case 3 the list it says null...
public class MediaItem {
String title;
MediaItem(){
}
MediaItem(String title){
[Code] ......
I have been having trouble with a recent hw assignment requiring us to sort user defined data types in an array. so far, i have implemented the sorting algorithms correctly but i cant seem to store a string and an integer together. I have an employee class
[public class employee {
private String Name;
private int IdNumber;
public employee(int IdNumber,String Name){
this.Name=Name;
this.IdNumber=IdNumber;}
[Code] .....
And in my app, i create a employee object-----> employee john=new employee(1020, "John");
How can I prompt my insert method to take in employee id and string name together?
package com.practice;
public class Car {
private String name; //name of the car
private String modelName; //Name of the model
private int year; //The year car was made in
private int speed=0;
[Code] ...
It wont let me copy it into a array is there any solution to this.