how are static method calls handled by the JVM? does it still allocate memory when a call is made? if yes, how does garbage collection treat this allocation after the method call?
I need to split a text using the separator ". ". For example I want this string :
Washington is the U.S Capital. Barack is living there.
To be cut into two parts:
Washington is the U.S Capital.
Barack is living there.
Here is my code :
// Initialize the tokenizer
StringTokenizer tokenizer = new StringTokenizer("Washington is the U.S Capital. Barack is living there.", ". ");
while (tokenizer.hasMoreTokens()) {
System.out.println(tokenizer.nextToken());
}
And the output is unfortunately :
Washington
is
the
U
S
Capital
Barack
is
living
there
Can someone explain what's going on?
I am trying to move a JComponent say a label over a table.I am tracking this event using MouseMotionListener's mouseDragged method.This method perfectly helps me in tracking the item.Is there a way to track the mouse release after dragging is complete(.ie the dropping event).
tktLabel1.addMouseMotionListener(new MouseMotionListener()
{
public void mouseDragged(MouseEvent arg0)
{
tktLabel1.setBounds(tktLabel1.getX() + arg0.getX(),
tktLabel1.getY() + arg0.getY(), width, height);
}
public void mouseMoved(MouseEvent arg0)
{
}
});
Hi,
I have an arraylist set up. I have input instuctions set up too, so that the user can enter one string, then one integer, then one string (the first name, the age, and the last name).
I need to sort the arraylist by the last name. The code I have entered so far is all under the main method:-
public static void main(String[] args) {
Name Name[] = new Name[50];
int count = 0;
for (int i=0; i<50; i++)
NewName[i] = new Name();
//ADD NEW TO ARRAYLIST NAME
String FName = JOptionPane.showInputDialog("first name");
int age = Integer.parseInt(JOptionPane.showInputDialog("age"));
String LName = JOptionPane.showInputDialog("last name");
NewName[count] = new Name(FName, age, LName);
count = count++;
}
//ITEMS SORT BY LAST NAME
//CODE FOR SORT GOES HERE
Dear All:
Was wondering, which is correct:
Option One
class A {
public void methodOne() {
synchronized(this) {
modifyvalue
notifyAll()
}
}
public void methodTwo() {
while (valuenotmodified) {
synchronized(this) {
wait()
}
}
}
Option Two
class A {
public void methodOne() {
modifyvalue
synchronized(this) {
notifyAll()
}
}
public void methodTwo() {
while (valuenotmodified) {
synchronized(this) {
wait()
}
}
}
and why?
Thank you
Misha
I am trying to get the ip of a socket connection in string form.
I am using a framework, which returns the SocketAddress of the recieved message. How can i transform it to InetSocketAddress or InetAddress?
I can understand why network apps would use multiplexing (to not create too many threads), and why programs would use async calls for pipelining (more efficient). But I don't understand the purpose of AsynchronousFileChannel.
Any ideas?
i want to know how to get the string from group of string
String j = "<a href=\"/watch?v=4Qx-lBqOqiQ&feature=popular\" onclick=\"\" onmousedown=\"yt.analytics.urchinTracker(\'/Events/Home/PersonalizedHome/POP/Logged_Out');\" ><span class=\"video-thumb video-thumb-220 \" id=\"video-thumb-4Qx-lBqOqiQ-8821469\"><img src=\"http://i1.ytimg.com/vi/4Qx-lBqOqiQ/hqdefault.jpg\" class=\"vimg220\" alt=\"Dog Squirrel Chasing A Squirrel\" title=\"Dog Squirrel Chasing A Squirrel\" onclick=\";yt.www.watch.watch5.IEshenanigans(event, this)\"><span class=\"video-time\"><span>1:08</span></span><span class=\"video-actions\"><button class=\"yt-uix-button-short yt-uix-button yt-uix-button-arrowbutton\" onclick=\"; return false;\" type=\"button\"> <img class=\"yt-uix-button-arrow\" src=\"http://s.ytimg.com/yt/img/pixel-vfl73.gif\" alt=\"\"> hai</a>";
i want to get the string href=\"/watch?v=4Qx-lBqOqiQ&feature=popular\" and src=\"http://i1.ytimg.com/vi/4Qx-lBqOqiQ/hqdefault.jpg\"
thanks and advance
Hi, i have a loaded image from disk (stored as a BufferedImage), which i display correctly on a JPanel but when i try to re-save this image using the command below, the image is saved in a reddish hue.
ImageIO.write(image, "jpg", fileName);
Note! image is a BufferedImage and fileName is a File object pointing to the filename that will be saved which end in ".jpg".
I have read that there were problems with ImageIO methods in earlier JDKs but i'm not on one of those versions as far as i could find. What i am looking for is a way to fix this issue without updating the JDK, however having said that i would still like to know in what JDK this issue was fixed in (if it indeed is still a bug with the JDK i'm using).
Thanks.
Suppose I have a string that contains '¿'. How would I find all those unicode characters? Should I test for their code? How would I do that?
I want to detect it to avoid sax parser exception which I am getting it while parsing the xml
saved as a clob in oracle 10g database.
Exception
javax.servlet.ServletException: org.xml.sax.SAXParseException: Invalid byte 1 of 1-byte UTF-8 sequence.
In a JVM the memory is split into Method Area ,Stack ,Heap , Temp and Registry . what is String Local Memory ? Does this exists ? If so when does it gets allocated or assigned ?
Appropriate Usage of this ?
Thanks
when looping, for instance:
for ( int j = 0; j < 1000; j++) {}; and I need to instantiate 1000 objects, how does it differ when I declare the object inside the loop from declaring it outside the loop ??
for ( int j = 0; j < 1000; j++) {Object obj; obj =}
vs
Object obj;
for ( int j = 0; j < 1000; j++) {obj =}
It's obvious that the object is accessible either only from the loop scope or from the scope that is surrounding it. But I don't understand the performance question, garbage collection etc.
What is the best practice ? Thank you
I am writing a simple multithreaded socketserver and I am wondering how best to handle incoming connections:
create a new thread for each new connection. The number of concurrent threads would be limited and waiting connections limited by specifying a backlog
add all incoming connections into a queue and have a pool of worker threads that process the queue
I am inclined to go for option 2 because I really don't want to refuse any connections, even under high loads, but I am wondering if there are any considerations I should be aware of with accepting effectively unlimited connections?
Hello, I know the following code could extract whole texts of the docx document, however, I need to extract paragraph instead. Is there are possible way??
public static String extractText(InputStream in) throws Exception {
JOptionPane.showMessageDialog(null, "Start extracting docx");
XWPFDocument doc = new XWPFDocument(in);
XWPFWordExtractor ex = new XWPFWordExtractor(doc);
String text = ex.getText();
return text;
}
Any helps would much appreciated. I need this so urgently.
I have a program where I am generating two double numbers by adding several input prices from a file based on a condition.
String str;
double one = 0.00;
double two = 0.00;
BufferedReader in = new BufferedReader(new FileReader(myFile));
while((str = in.readLine()) != null){
if(str.charAt(21) == '1'){
one += Double.parseDouble(str.substring(38, 49) + "." + str.substring(49, 51));
}
else{
two += Double.parseDouble(str.substring(38, 49) + "." + str.substring(49, 51));
}
}
in.close();
System.out.println("One: " + one);
System.out.println("Two: " + two);
The output is like:
One: 2773554.02
Two: 6.302505836000001E7
Question:
None of the input have more then two decimals in them. The way one and two are getting calculated exactly same.
Then why the output format is like this.
What I am expecting is:
One: 2773554.02
Two: 63025058.36
Why the printing is in two different formats ? I want to write the outputs again to a file and thus there must be only two digits after decimal.
hi,
need to convert a pdf file to a doc file. I found different type of example to generate pdf file but not got pdf to doc.
please help me in this regard with good example or source code or guideline.
I have the following code in struts.xml:
<interceptor-ref name="checkTabsStack">
<param name="tabName">availability</param>
</interceptor-ref>
and I want to access the parameter tabName in the interceptor routine, how do i do that? i tried
Map params = ActionContext.getContext().getParameters();
but params comes empty...
Thanks!
I am relatively new to multi-threading and want to execute a background task using a Swingworker thread - the method that is called does not actually return anything but I would like to be notified when it has completed.
The code I have so far doesn't appear to be working:
private void crawl(ActionEvent evt)
{
try
{
SwingWorker<Void, Void> crawler = new SwingWorker<Void, Void>()
{
@Override
protected Void doInBackground() throws Exception
{
Discoverer discover = new Discoverer();
discover.crawl();
return null;
}
@Override
protected void done()
{
JOptionPane.showMessageDialog(jfThis, "Finished Crawling", "Success", JOptionPane.INFORMATION_MESSAGE);
}
};
crawler.execute();
}
catch (Exception ex)
{
JOptionPane.showMessageDialog(this, ex.getMessage(), "Exception", JOptionPane.ERROR_MESSAGE);
}
}
Any feedback/advice would be greatly appreciated as multi-threading is a big area of programming that I am weak in.
What complexity are the methods multiply, divide and pow in BigInteger currently? There is no mention of the computational complexity in the documentation (nor anywhere else).
Here's what I am looking to accomplish, I have a class that has an enum of some values and I want to subclass that and add more values to the enum. This is a bad example, but:
public class Digits
{
public enum Digit
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
}
}
public class HexDigits extends Digits
{
public enum Digit
{
A, B, C, D, E, F
}
}
so that HexDigits.Digit contains all Hex Digits. Is that possible?
Right, this is from an older exam which i'm using to prepare my own exam in january. We are given the following method:
public static void Oorspronkelijk()
{
String bs = "Dit is een boodschap aan de wereld";
int max = -1;
char let = '*';
for (int i=0;i<bs.length();i++) {
int tel = 1;
for (int j=i+1;j<bs.length();j++) {
if (bs.charAt(j) == bs.charAt(i)) tel++;
}
if (tel > max) {
max = tel;
let = bs.charAt(i);
}
}
System.out.println(max + " keer " + let);
}
The questions are:
what is the output? - Since the code is just an algorithm to determine the most occuring character, the output is "6 keer " (6 times space)
What is the time complexity of this code?
Fairly sure it's O(n²), unless someone thinks otherwise?
Can you reduce the time complexity, and if so, how?
Well, you can. I've received some help already and managed to get the following code:
public static void Nieuw()
{
String bs = "Dit is een boodschap aan de wereld";
HashMap<Character, Integer> letters = new HashMap<Character, Integer>();
char max = bs.charAt(0);
for (int i=0;i<bs.length();i++) {
char let = bs.charAt(i);
if(!letters.containsKey(let)) {
letters.put(let,0);
}
int tel = letters.get(let)+1;
letters.put(let,tel);
if(letters.get(max)<tel) {
max = let;
}
}
System.out.println(letters.get(max) + " keer " + max);
}
However, I'm uncertain of the time complexity of this new code: Is it O(n) because you only use one for-loop, or does the fact we require the use of the HashMap's get methods make it O(n log n) ?
And if someone knows an even better way of reducing the time complexity, please do tell! :)
hi,
first time dealing with xml, so please be patient. the code below is probably evil in a million ways (I'd be very happy to hear about all of them), but the main problem is of course that it doesn't work :-)
public class Test {
private static final String JSDL_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl";
private static final String JSDL_POSIX_APPLICATION_SCHEMA_URL = "http://schemas.ggf.org/jsdl/2005/11/jsdl-posix";
public static void main(String[] args) {
System.out.println(Test.createJSDLDescription("/bin/echo", "hello world"));
}
private static String createJSDLDescription(String execName, String args) {
Document jsdlJobDefinitionDocument = getJSDLJobDefinitionDocument();
String xmlString = null;
// create the elements
Element jobDescription = jsdlJobDefinitionDocument.createElement("JobDescription");
Element application = jsdlJobDefinitionDocument.createElement("Application");
Element posixApplication = jsdlJobDefinitionDocument.createElementNS(JSDL_POSIX_APPLICATION_SCHEMA_URL, "POSIXApplication");
Element executable = jsdlJobDefinitionDocument.createElement("Executable");
executable.setTextContent(execName);
Element argument = jsdlJobDefinitionDocument.createElement("Argument");
argument.setTextContent(args);
//join them into a tree
posixApplication.appendChild(executable);
posixApplication.appendChild(argument);
application.appendChild(posixApplication);
jobDescription.appendChild(application);
jsdlJobDefinitionDocument.getDocumentElement().appendChild(jobDescription);
DOMSource source = new DOMSource(jsdlJobDefinitionDocument);
validateXML(source);
try {
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
StreamResult result = new StreamResult(new StringWriter());
transformer.transform(source, result);
xmlString = result.getWriter().toString();
} catch (Exception e) {
e.printStackTrace();
}
return xmlString;
}
private static Document getJSDLJobDefinitionDocument() {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = null;
try {
builder = factory.newDocumentBuilder();
} catch (Exception e) {
e.printStackTrace();
}
DOMImplementation domImpl = builder.getDOMImplementation();
Document theDocument = domImpl.createDocument(JSDL_SCHEMA_URL, "JobDefinition", null);
return theDocument;
}
private static void validateXML(DOMSource source) {
try {
URL schemaFile = new URL(JSDL_SCHEMA_URL);
Sche maFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
Schema schema = schemaFactory.newSchema(schemaFile);
Validator validator = schema.newValidator();
DOMResult result = new DOMResult();
validator.validate(source, result);
System.out.println("is valid");
} catch (Exception e) {
e.printStackTrace();
}
}
}
it spits out a somewhat odd message:
org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'JobDescription'. One of '{"http://schemas.ggf.org/jsdl/2005/11/jsdl":JobDescription}' is expected.
Where am I going wrong here?
Thanks a lot
Hello,
Im using Collections.sort() to sort a LinkedList whose elements implements Comparable interface, so they are sorted in a natural order. In the javadoc documentation its said this method uses mergesort algorithm wich has n*log(n) performance.
My question is if there is a more efficient algorithm to sort my LinkedList?
The size of that list could be very high and sort will be also very frequent.
Thanks!