Search Results

Search found 32961 results on 1319 pages for 'java 8'.

Page 435/1319 | < Previous Page | 431 432 433 434 435 436 437 438 439 440 441 442  | Next Page >

  • Java: how do I get a class literal from a generic type?

    - by Tom
    Typically, I've seen people use the class literal like this: Class<Foo> cls = Foo.class; But what if the type is generic, e.g. List? This works fine, but has a warning since List should be parameterized: Class<List> cls = List.class So why not add a <?>? Well, this causes a type mismatch error: Class<List<?>> cls = List.class I figured something like this would work, but this is just a plain ol' a syntax error: Class<List<Foo>> cls = List<Foo>.class How can I get a Class<List<Foo>> statically, e.g. using the class literal? I could use @SuppressWarnings("unchecked") to get rid of the warnings caused by the non-parameterized use of List in the first example, Class<List> cls = List.class, but I'd rather not. Any suggestions? Thanks!

    Read the article

  • JAVA: 500 Worker Threads, what kind of thread pool?

    - by Submerged
    I am wondering if this is the best way to do this. I have about 500 threads that run indefinitely, but Thread.sleep for a minute when done one cycle of processing. ExecutorService es = Executors.newFixedThreadPool(list.size()+1); for (int i = 0; i < list.size(); i++) { es.execute(coreAppVector.elementAt(i)); //coreAppVector is a vector of extends thread objects } I do need a separate threads for each running task, so changing the architecture isn't an option. I tried making my threadPool size equal to Runtime.getRuntime().availableProcessors() which attempted to run all 500 threads, but only let 8 (4xhyperthreading) of them execute. The other threads wouldn't surrender and let other threads have their turn. I tried putting in a wait() and notify(), but still no luck. If anyone has a simple example or some tips, I would be grateful!

    Read the article

  • How can I rotate an image using Java/Swing and then set its origin to 0,0?

    - by JT
    I'm able to rotate an image that has been added to a JLabel. The only problem is that if the height and width are not equal, the rotated image will no longer appear at the JLabel's origin (0,0). Here's what I'm doing. I've also tried using AffineTransform and rotating the image itself, but with the same results. Graphics2D g2d = (Graphics2D)g; g2d.rotate(Math.toRadians(90), image.getWidth()/2, image.getHeight()/2); super.paintComponent(g2d); If I have an image whose width is greater than its height, rotating that image using this method and then painting it will result in the image being painted vertically above the point 0,0, and horizontally to the right of the point 0,0.

    Read the article

  • Is it bad to explicitly compare against boolean constants e.g. if (b == false) in Java?

    - by polygenelubricants
    Is it bad to write: if (b == false) //... while (b != true) //... Is it always better to instead write: if (!b) //... while (!b) //... Presumably there is no difference in performance (or is there?), but how do you weigh the explicitness, the conciseness, the clarity, the readability, etc between the two? Note: the variable name b is just used as an example, ala foo and bar.

    Read the article

  • How to fill two-dimensional array using java enhanced loop?

    - by Shark
    Basically, I am trying this, but this only leaves array filled with zeros. I know how to fill it with normal for loop (such as for (int i = 0; i < array.length; i++) and so on), but why is my variant is not working? Any help would be appreciated. char[][] array = new char[x][y]; for (char[] row : array) for (char element : row) element = '~';

    Read the article

  • Spring Jdbc Template + MySQL = TransientDataAccessResourceException : Invalid Argument Value : Java.

    - by Vanchinathan
    I was using spring jdbc template to insert some data into the database and I was getting this error. Here is my code : JdbcTemplate insert = new JdbcTemplate(dataSource); for(ResultType result : response.getResultSet().getResult()) { Object[] args = new Object[] {result.getAddress(), result.getCity(), result.getState(), result.getPhone(), result.getLatitude(), result.getLongitude(),result.getRating().getAverageRating(), result.getRating().getAverageRating(), result.getRating().getTotalRatings(), result.getRating().getTotalReviews(), result.getRating().getLastReviewDate(), result.getRating().getLastReviewIntro(), result.getDistance(), result.getUrl(), result.getClickUrl(), result.getBusinessUrl(), result.getBusinessClickUrl()}; insert.update("INSERT INTO data.carwashes ( address, city, state, phone, lat, lng, rating, average_rating, total_ratings, total reviews, last_review_date, last_review_intro, distance, url, click_url, business_url, business_click_url, category_id, zipcode_id) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?,96925724,78701)", args); } Quite lengthy code.. but, basically it gets the value from a object and sticks it to a array and passed that array to insert method of jdbc template. Any help will be appreciated.

    Read the article

  • Java - Adding a Node in a doubly-linked list.

    - by jacobnlsn
    Hi, I am working on some code were I need to add a Node into a doubly linked-list, this is the code I have so far: Node tempNext = cursor.getNext(); temp = new Node(item, null, cursor, tempNext); tempNext.setPrev(temp); cursor is the Node that is right before the new added Node should go.

    Read the article

  • How do you draw a string centered vertically in Java?

    - by Paul Alexander
    I know it's a simple concept but I'm struggling with the font metrics. Centering horizontally isn't too hard but vertically seems a bit difficult. I've tried using the FontMetrics getAscent, getLeading, getXXXX methods in various combinations but no matter what I've tried the text is always off by a few pixels. Is there a way to measure the exact height of the text so that it is exactly centered.

    Read the article

  • how to read data from file into array? java

    - by lox
    I need some help reading data from a txt file into my ArrayList. I know the code is pretty messy, but just try to take a look at it. The first part with the creating and putting the ArrayList into the txt file works perfectly. I just need some help at the end in the "marked" area. Sorry if I still have some words in my native language, but I didn't really had the time to translate everything. public class ContAngajat { String username; String password; } public class CreazaCont { // creating the arraylist and putting it into a file public static void ang(String args[]) { ArrayList<ContAngajat> angajati=new ArrayList<ContAngajat>(50); Scanner diskScanner = new Scanner(in); Scanner forn = new Scanner(in); int n; out.print("Introduceti numarul de conturi noi care doriti sa le introduceti: "); n=forn.nextInt(); out.println(); try{ FileWriter fw = new FileWriter("ConturiAngajati.txt", true); for(int i=0; i<n; i++){ ContAngajat cont = new ContAngajat(); out.print("Username: "); cont.username=diskScanner.nextLine(); out.print("Password: "); cont.password=diskScanner.nextLine(); angajati.add(cont); fw.write(cont.username + " "); fw.write(cont.password +"|"); } fw.close(); } catch(IOException ex){ System.out.println("Could not write to file"); System.exit(0); } for (int i=0; i<n; i++) { out.println("username: " + angajati.get(i).username + " password: " +angajati.get(i).password ); } } // HERE I'M TRING TO GET THE ARRAYLIST OUT OF THE FILE public static void RdAng(String args[]) { ArrayList<ContAngajat> angajati=new ArrayList<ContAngajat>(50); ContAngajat cont = new ContAngajat(); int count,i2,i; try{ FileReader fr = new FileReader("ConturiAngajati.txt"); BufferedReader br = new BufferedReader(fr); String line = ""; while((line=br.readLine())!=null) { String[] theline=line.split("|"); count=theline.length; for(i=0;i<theline.length;i++) { String[] theword = theline[i].split(" "); } } for(i2=0;i2<count;i2++) { ContAngajat contrd = new ContAngajat(); // "ERROR" OVER HERE for (int ird=0; ird <theword.length; ird++) { cont.username=theword[0]; cont.password=theword[1]; // they keep telling me "theword cannot be resolved" whenever i try to run this } angajati.add(contrd); } } catch(IOException ex){ System.out.println("Could not read to file"); System.exit(0); } } }

    Read the article

  • Java: Selected rows's index does not changes when I sort them!

    - by adrian7
    Hello, I have a Jtable on which I called the method table1.setAutoCreateRowSorter(true);. So this works on well. But I also have a methos in my JFrame class which is fired when i push a button. It gets the selected rows indexes using this code int selectedRows[] = this.table1.getSelectedRows();. And displays an edit window for the first row corresponding in the selected interval. The problem is that if I don't click on column's headers (I mean i don't sorte them at all) my method works perfect. But when I sort the row, the indexes of the rows doesn't seems to change at all - thus resulting an edit window for the old row whicn was initially in that position before making any sort. I am using JDK 6 could anyonw give ma a tip?

    Read the article

  • Is there anything bad in declaring static inner class inside interface in java?

    - by Roman
    I have an interface ProductService with method findByCriteria. This method had a long list of nullable parameters, like productName, maxCost, minCost, producer and so on. I refactored this method by introducing Parameter Object. I created class SearchCriteria and now method signature looks like this: findByCriteria (SearchCriteria criteria) I thought that instances of SearchCriteria are only created by method callers and are only used inside findByCriteria method, i.e.: void processRequest() { SearchCriteria criteria = new SearchCriteria () .withMaxCost (maxCost) ....... .withProducer (producer); List<Product> products = productService.findByCriteria (criteria); .... } and List<Product> findByCriteria(SearchCriteria criteria) { return doSmthAndReturnResult(criteria.getMaxCost(), criteria.getProducer()); } So I did not want to create separate public class for SearchCriteria and put it inside ProductServiceInterface: public interface ProductService { List<Product> findByCriteria (SearchCriteria criteria); static class SearchCriteria { ... } } Is there anything bad in this interface? Where whould you place SearchCriteria class?

    Read the article

  • Array inside of Arrays; Java (Help with Lab Assignment)

    - by Adam
    We are working on a lab assignment for my CS&E class and I think I can ask this question without going into detail of the entire lab requirements, but is it possible for an array to be inside of an array? For example, would this work: int [] arrayOne = new int[3]; arrayOne[0] = Start of an array If this is possible how do you go about doing it?

    Read the article

  • How do we simplify this kind of code in Java? Something like macros in C?

    - by Terry Li
    public static boolean diagonals(char[][] b, int row, int col, int l) { int counter = 1; // because we start from the current position char charAtPosition = b[row][col]; int numRows = b.length; int numCols = b[0].length; int topleft = 0; int topright = 0; int bottomleft = 0; int bottomright = 0; for (int i=row-1,j=col-1;i>=0 && j>=0;i--,j--) { if (b[i][j]==charAtPosition) { topleft++; } else { break; } } for (int i=row-1,j=col+1;i>=0 && j<=numCols;i--,j++) { if (b[i][j]==charAtPosition) { topright++; } else { break; } } for (int i=row+1,j=col-1;i<=numRows && j>=0;i++,j--) { if (b[i][j]==charAtPosition) { bottomleft++; } else { break; } } for (int i=row+1,j=col+1;i<=numRows && j<=numCols;i++,j++) { if (b[i][j]==charAtPosition) { bottomright++; } else { break; } } return topleft + bottomright + 1 >= l || topright + bottomleft + 1 >= l; //in this case l is 5 } After I was done posting the code above here, I couldn't help but wanted to simplify the code by merging the four pretty much the same loops into one method. Here's the kind of method I want to have: public int countSteps(char horizontal, char vertical) { } Two parameters horizontal and vertical can be either + or - to indicate the four directions to walk in. What I want to see if possible at all is i++; is generalized to i horizontal horizontal; when horizontal taking the value of +. What I don't want to see is if or switch statements, for example: public int countSteps(char horizontal, char vertical) { if (horizontal == '+' && vertical == '-') { for (int i=row-1,j=col+1;i>=0 && j<=numCols;i--,j++) { if (b[i][j]==charAtPosition) { topright++; } else { break; } } } else if (horizontal == '+' && vertical == '+') { for (int i=row+1,j=col+1;i>=0 && j<=numCols;i++,j++) { if (b[i][j]==charAtPosition) { topright++; } else { break; } } } else if () { } else { } } Since it is as tedious as the original one. Note also that the comparing signs for the loop condition i>=0 && j<=numCols; for example, >= && <= have correspondence with the value combination of horizontal and vertical. Sorry for my bad wording, please let me know if anything is not clear.

    Read the article

  • Best way to identify and dispose locked thread in java.

    - by Bala R
    I have to call a function 3rd party module on a new thread. From what I've seen, the call either completes quickly if everything went well or it just hangs for ever locking up the thread. What's a good way to start the thread and make the call and wait for a few secs and if the thread is still alive, then assuming it's locked up, kill (or stop or abandon) the thread without using any deprecated methods. I have something like this for now, but I'm not sure if this is the best way to do it and I want to avoid calling Thread.stop() as it's deprecated. Thanks. private void foo() throws Exception { Runnable runnable = new Runnable() { @Override public void run() { // stuff that could potentially lock up the thread. } }; Thread thread; thread = new Thread(runnable); thread.start(); thread.join(3500); if (thread.isAlive()) { thread.stop(); throw new Exception(); } }

    Read the article

< Previous Page | 431 432 433 434 435 436 437 438 439 440 441 442  | Next Page >