In the case that vehicle.color is null what will happens? A null pointer error?
null will be concatenated to the string in vehicle.color place? or will not concatenate anything in the place of vehicle.color I'm asking that because I do not know if I have to check for null in each property of vehicle that I must concatenate (there are a lot of properties in the Vehicle object and some may not been set (they will return null).
I've been beavering away with Java for a few months. But as with all languages the String implementation looks designed to trip up even experienced programmers.
My current development gets data from various sources outside my control. When I get a string I want to test if it is empty/null/or whatever. Simple enough one thinks.
But if you search the internet you see everone seems to have a slightly different approach. So what is the best way of determining that a string is not useful to you?
I've had success with this
if(string == null || string.length() == 0)
But I've seen people using methods - not necessarily of String (e.g equals, empty) and regular expressions.
What is the best approach to this considering coding efficiency and/or processing efficiency (accepting you'd have to be processing a lot of strings for the latter to be an issue).
I have table data I'm trying to read . However one column is populated with the word "null". I guess java does not like dealing with the word null and throws errors.
When I try a block like : if ( rsrow.getString(insCol) = "null") {
I get and error .
If I try :
cmp = rsrow.getString(insCol);If I try:If I try: if (cmp = "null") {
I get an error
If I try to use a replace function like:
System.out.println(cmp.replace("null", "0"));
Just to see if replace works I get and error.
What is the BEST way to replace this string value with something like "0" when I come across it with out jave throwing an error? I want it such that every time I come across the word "null" I can repalce it with "0".
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
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?
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 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.
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:
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 have to create another xml doc with the properties of nodes from the first doc. For the new doc I have to create a parent node called "definitions". Instead of the "model" node in the first doc I have to create a "process" node in the new doc that has an attribute "id" which value is the same as the content of the "id" child node of model. For each "nodes" node in the first doc if their "stencil" child node content equals "TASK" I create a "task" node in the new xml doc.
I just wanted to know if this is the correct way to define the respective classes.any way to create and fill the nodes for the new doc using this classes? I am used with DOM parser and I know how to create nodes and fill attribute values, but I have always done this job in a single class, not using different classes for the elements.
So I am trying to add a logo to my existing program. However nothing shows up when I run it. I am getting no errors and everything else seems to be fine. This is just the logo part if you need the whole code it will be separate (just trying to make things easier.
class Logo extends JPanel { public Logo() { super(); setPreferredSize(new Dimension(200,200)); } public void paint(Graphics g) { g.setColor(Color.red); g.fillRoundRect(60,60,110,90,5,5); g.setColor(Color.black); g.drawString("DEAD BUG", 70, 105);
I have an EJB project which is deployed in Webaphere 7 and i do not have source code for that project.I know the EJB session bean class name, can i generate the client for this class/project to invoke the session bean?
I would like to make an incremental change to an existing Java program. And the program has been installed on the user's machine. Now I only want to do an incremental download (to minimize the download time) to update the program.
I do most of my file I/O with {Scanner} for input and {PrintWriter} for output. I've got lots of places in my code that looks like:
Scanner source = new Scanner( new File( sourceName)); PrintWriter dstntn = new PrintWriter( new BufferedWriter( new FileWriter( dstntnName)));
But when I call the constructor for {PrintWriter} up above, it overwrites whatever the original contents of the file designated by {dstntnName} were, doesn't it? Is there a way to call the constructor so that any future writes to it simply append to the original contents, instead of overwriting them?
I am trying to mavenize an existing enterprise application and this application has EJB, MDB and MQs. As far as the folder structure is concerned, it has a project that creates an ear file, and has one for project for web and another project for EJBs. there is one more project that holds some property file.
I am trying to mavenize this this application, so that I am able to create an ear of application containing the war of web project, jars of property project and ejb project and I am badly stuck.
I know there was a change in the later versions of Java where the C++ equivalent of a <template type> was added. Unfortunately the change has 'broken' my older code. If I have a JList and I want to add elements to it then now I should specify the type e.g., the list will store Strings. When I do this and then add data to the list (or actually the list model) the code is ''fixed". However if after adding those new elements to the list I later need to add more elements, which isn't unreasonable for a list...to have elements added dynamically at run time then I again get the same compiler error message that I haven't correctly specified the type:
// Error message during compilation Note: Driver.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details.
// My code
// Problem here: I try to add new elements to the list. It's the very last line of the method that results in the error. I tried various things such as:
// model.addElement(<String> s); // but so far nothing has worked. How do I add new elements to the list (model)? public static void m2(JList <String> list) { String s; int i; String [] array = new String[10];
[Code] ....
// Code is OK: Create the array of strings to add to constructor of the JList
public static String[] m1(){ String s; int i; String [] array = new String[10]; for (i = 0; i < 5; i++) array[i] = i + "*"; return(array);
[Code] ....
// The change I had to make when compiling under the newer version of Java to indicate that the list would store strings
// Things are okay here now but then when I try to add new elements to the model via method 'm2' that's where I get the compiler error
I am trying to create a code which allows the users to create JButtons to a an existing frame.So what I want is that users can create buttons wihch opens a URL. The user need to be able to click on an Existing JButton called "Add Favorite", insert the name of the favorite and URL and the button is added with the functionality to open the URL in Internet Explorer.
I already have a beginning but have no clue how to add that functionaly to create JButton by pressing on button "Add Favorites" with the needed functionality The functionality needes to be added to Button4 ("add Favorite" ). As you can see, Button4 ("add Favorite") opens two inputShowDialog which allows the users to insert the name of the favorite and URL.
import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.JButton.*; import java.awt.Dimension.*; import java.lang.RuntimeException.*; import javax.swing.JOptionPane; public class Favorites extends JFrame implements ActionListener{ //private JPanel panel1 = new Jpanel ("Add Favorite");
I am modifying existing code to display graph after pressing calculate button. The graph pop ups in new controller/window. The pop up disappears after closing the application entirely. However I have trouble figuring out if it is possible to close that old/previous pop up and new pop up appears when calculate button is pressed again. Or at least reuse the pop up to display a new graph.
public class AdamCalculationApp extends AbstractCalculation { /** * Does a calculation. */ public void calculate() { // Does a calculation control.println("Adam Calculation button pressed."); double k = control.getDouble("k value"); // String must match argument of setValue control.println("k*k = "+(k*k)); control.println("random = "+Math.random());
I have a project of biometric integration by java and i have that javaApi with me for that project i need to add native libraries through NetBeansIDE7.4. I am trying like this
Right click on the ProjectSelect PropertiesClick on RUNIn VM Options TYPE -Djava.library.path="D:/bio-metric/SBXPC_CORE_130330/SBXPCJavaProxy.dll" press Ok but still I am getting Exception java.lang.UnsatisfiedLinkError: no SBXPCJavaProxy in java.library.path
I have a Linux Server Debian 7 x86_64 Minimal With java version "1.7.0_65" installed..Its an online Game Server wich Players can join just like other Services.Every 10 - 15 minutes all the players get kicked from the server and get this messege: "internal exception: java.io.ioexception: an existing connection was forcibly closed by remote host"
The players can't join the server for 10 seconds and the server console doesn't show anything for 10 seconds.it doesnt show that the players even left! and when the players try to join they get htis messege: "same nick is already playing"
After 10 seconds everything will work and players can join again and server console say that everyone left and joined..But that happens again after 10 minutes and im losing lots of players because of this error.
I want to embed an existing JAVA applet in to my swing application which is a standalone application. The applet is used in some other application which is not developed by me or my company. The application is open source application (So I have the source code). The entire existing application is basically one of the parts of my new application.
