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  • Java newbie problem: package with private access

    - by HH
    Pack.java imports pack.TestPack; but it cannot access it. I cannot understand why it cannot access the class despite the import. Error Pack.java:7: TestPack() is not public in pack.TestPack; cannot be accessed from outside package System.out.println(new TestPack().getHello()); ^ 1 error Pack.java import pack.TestPack; import java.io.*; public class Pack { public static void main(String[] args){ System.out.println(new TestPack().getHello()); } } TestPack.java package pack; import java.util.*; import java.io.*; public class TestPack { private String hello="if you see me, you ar inside class TestPack"; public String getHello(){return hello;} TestPack(){} }

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  • Dynamically create and cast objects at runtime

    - by vaibhav bindroo
    Let's say we have 2 classes A and B public class A{ private int member1; A() { member1 = 10; } public getMember(){ return member1; } } Class B is also on the same lines except that its member variable is named member2 and gets intitialized to say 20 inside the constructor. My Requirement : At runtime , I get a string which contains a className ( could be A or B). I want to dynamically create an object of this class along with invoking the constructor. How can I achieve this . I don't want to use interfaces for common functionality of above classes Morever, later on I set the properties of this raw object using Propery Builder Bean Util class based on a list of columns . Class clazz = Class.forName("className"); Obj obj = clazz.newInstance(); How I can dynamically convert that obj to className object.

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  • Java: JPA classes, refactoring from Date to DateTime

    - by bguiz
    With a table created using this SQL Create Table X ( ID varchar(4) Not Null, XDATE date ); and an entity class defined like so @Entity @Table(name = "X") public class X implements Serializable { @Id @Basic(optional = false) @Column(name = "ID", nullable = false, length = 4) private String id; @Column(name = "XDATE") @Temporal(TemporalType.DATE) private Date xDate; //java.util.Date ... } With the above, I can use JPA to achieve object relational mapping. However, the xDate attribute can only store dates, e.g. dd/MM/yyyy. How do I refactor the above to store a full date object using just one field, i.e. dd/MM/yyyy HH24:mm?

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  • Is this casting safe?

    - by Itsik
    I need to write a Util function (in my c++cli app) that converts a String to a Double or Float or Int. template<typename T> static T MyConvert(String^ str) { return static_cast<T>(System::Convert::ToDouble(str)); } Is this safe? Can it somehow convert 2 to 1.999 and then to 1 if I call MyConvert<int>("2") ? I was wondering why the Convert class isn't templated in the first place? (That would let me call Convert<T> instead of Convert.ToDouble() for all types) This is C++/Cli so I can use any convert methods in c++ or .net, but I only know Convert.ToDouble()|ToString()|ToInt32()) Thanks

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  • How to customize Json serialization using Scala and Play Framework?

    - by Jonas
    I would like to serialize some Scala case classes to Json. E.g my case class looks like: case class Item ( id: Int, name: String, price: BigDecimal, created: java.util.Date) and I would like to serialize it to Json like this: {"id":3, "name": "apple", "price": 8.00, "created": 123424434} so I need a custom serilization for BigDecimal and for Date. Where I want the data in milliseconds since 1 jan 1970. When using Scala and Play Framework, I can return Json using Json(myObject), but how do I customize the serialization? Or is there any recommended Scala library?

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  • java best way to transfer images

    - by d.raev
    I have a application that reads a PDF, transform the content to collection of TIF files, and send them to Glass Fish Server for saving. Usually there are 1-5 pages and it works nice, but when I got a input file with 100+ pages... it throws error on the transfer. Java heap space at java.util.Arrays.copyOf(Arrays.java:2786) at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:94) Putting more resources is not a good option in my case, so I m looking for a way to optimize it somehow. I store the data in: HashMap<TifProfile, List<byte[]> Is there a better way to store or send them ? EDIT I did some tests and the final collections for PDF with 80 pages has size over 280mb (240 tiffs with different settings inside)

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  • What to do with missing fields in sunspot-rails?

    - by chrismealy
    I'm using sunspot/rails version 2. It's working great, but I can't figure out how to handle missing fields. If I don't have latitude and longitude this code will map it to 0,0 (near Africa): searchable do text :resume, :stored => true text :city, :boost => 5 latlon(:geo) { Sunspot::Util::Coordinates.new(latitude, longitude) } end I tried using two search blocks, each with a different conditional, but sunspot just uses the first searchable block. What I want to happen is for things missing locations to still be searchable, just not by location.

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  • Whats wrong with my Random?

    - by David
    Here's my import statement: import java.util.*; Here it is in main: Random Rand = new Random() ; Here it is in a public void method : int a - 0 ; while (!done) { int a = Rand.nextInt(10) ; if (debug) stuff ; if (possibles[a]==1) done = true ; } Here's the error message i get: TicTacToe.java:85: cannot find symbol symbol : method nextInt(int) location: class Rand a = Rand.nextInt(10) ; ^ Whats going wrong here? it seems like i've done everything right to me.

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  • How do I use Criteria to make a join on a date field (in DB2) based on the year.

    - by HtmlTableGuru
    I have a java.util.Date field in my Object. I would like to use Criteria to select all rows that have a date field with a given year. The SQL would look like the following: SELECT * FROM GAME GM WHERE YEAR(GM.GAME_DATE) = 2010 How can I use Criteria to accomplish this? Thanks in advance. public Collection<Game> getGamesByDate(Date date){ Collection<Game> games = null; try { session.beginTransaction(); Criteria criteria = session.createCriteria(Game.class); criteria .... ... ... games = criteria.list(); } catch (HibernateException e) { e.printStackTrace(); } return games; }

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  • Returning the index number of an Arraylist in Java

    - by Daniel
    I would like my method public void showClassRoomDetails(String teacherName) to return the Arraylist index number using the teacherName. Thanks import java.util.ArrayList; public class School { private ArrayList<Classroom> classrooms; private String classRoomName; private String teacherName; public School() { classrooms = new ArrayList<Classroom>(); } public void addClassRoom(Classroom newClassRoom, String theClassRoomName) { classrooms.add(newClassRoom); classRoomName = theClassRoomName; } public void addTeacherToClassRoom(int classroomId, String TeacherName) { if (classroomId < classrooms.size() ) { classrooms.get(classroomId).setTeacherName(TeacherName); } } public void showClassRoomDetails(String teacherName) { for (Classroom classroom : this.classrooms) { if (classroom.returnTeacherName().equals(teacherName)) { System.out.println(classroom.returnClassRoomName()); System.out.println(classroom.returnTeacherName()); break; } } } }

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  • setting java classpath for Libre Office Base in Fedora 16

    - by foampile
    using Fedora 16 OS. i want to use Libre Office Base to connect to MySQL. when i set up the JDBC connection, it asks me for the driver, however, it cannot be loaded (because it doesn't see it in the classpath). does anybody know how to set the classpath for Libre Office? is there like a config util tool for that? e.g. my driver is [B]com.mysql.jdbc.Driver [/B]situated in[B] /usr/share/java/mysql-connector-java-5.1.17.jar[/B]. it works fine when i connect from other JDBC clients, like straight Java or Eclipse Quantum plugin. the problem is that Libre Office does not ask me for the (class)path of where it can find the driver and i do not know where and how to set it so that it becomes visible. thanks

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  • Actionscript package naming and directory structure

    - by danwoods
    Hello all, I've got some actionscript which begins with: package obfus_plugin{ import org.flowplayer.model.Plugin; import org.flowplayer.util.Arrange; import org.flowplayer.model.PluginModel; import org.flowplayer.view.Flowplayer; and when I try to publish, I get the error: 5001: The name of package 'obfus_plugin' does not reflect the location of this file. Please change the package definition's name inside this file, or move the file. C:\Documents and Settings\***\My Documents\My Dropbox\Public\obfus_plugin\obfus_plugin.as In my classpaths I have: C:\Documents and Settings\***\My Documents\My Dropbox\Public What am I doing wrong?

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  • What are the pro and cons of having localization files vs hard coded variables in source code?

    - by corgrath
    Definitions: Files: Having the localization phrases stored in a physical file that gets read at application start-up and the phrases are stored in the memory to be accessed via util-methods. The phrases are stored in key-value format. One file per language. Variables: The localization texts are stored as hard code variables in the application's source code. The variables are complex data types and depending on the current language, the appropriate phrase is returned. Background: The application is a Java Servlet and the developers use Eclipse as their primary IDE. Some brief pro and cons: Since Eclipse is use, tracking and finding unused localizations are easier when they are saved as variables, compared to having them in a file. However the application's source code becomes bigger and bloated. What are the pro and cons of having localization text in files versus hard coded varibles in source code? What do you do and why?

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  • Netbeans Java SE GUI Builder: private initComponents() problem

    - by maSnun
    When I build a GUI for my Java SE app with Netbeans GUI builder, it puts all the codes in the initComponents() method which is private. I could not change it to public. So, all the components are accessible only to the class containing the UI. I want to access those components from another class so that I can write custom event handlers and everything. Most importantly I want to separate my GUI code and non-GUI from each other. I can copy paste the GUI code and later make them public by hand to achieve what I want. But thats a pain. I have to handcraft a portion whenever I need to re-design the UI. What I tried to do: I used the variable identifier to make the text box public. Now how can I access the text box from the Main class? I think I need the component generated in a public method as well. I am new to Java. Any helps? Here's the sample classes: The UI (uiFrame.java) /* * To change this template, choose Tools | Templates * and open the template in the editor. */ /* * uiFrame.java * * Created on Jun 3, 2010, 9:33:15 PM */ package barcode; import java.util.logging.Level; import java.util.logging.Logger; import javax.swing.JFileChooser; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; import net.sourceforge.barbecue.output.OutputException; /** * * @author masnun */ public class uiFrame extends javax.swing.JFrame { /** Creates new form uiFrame */ public uiFrame() { try { try { // Set cross-platform Java L&F (also called "Metal") UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException ex) { Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex); } catch (InstantiationException ex) { Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex); } catch (IllegalAccessException ex) { Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex); } catch (UnsupportedLookAndFeelException ex) { Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex); } } finally { } initComponents(); } /** This method is called from within the constructor to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { label1 = new javax.swing.JLabel(); textBox = new javax.swing.JTextField(); saveButton = new javax.swing.JButton(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); label1.setFont(label1.getFont().deriveFont(label1.getFont().getStyle() | java.awt.Font.BOLD, 13)); label1.setText("Type a text:"); label1.setName("label1"); // NOI18N saveButton.setText("Save"); saveButton.addMouseListener(new java.awt.event.MouseAdapter() { public void mousePressed(java.awt.event.MouseEvent evt) { saveButtonMousePressed(evt); } }); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(56, 56, 56) .addComponent(textBox, javax.swing.GroupLayout.PREFERRED_SIZE, 272, javax.swing.GroupLayout.PREFERRED_SIZE) .addContainerGap(72, Short.MAX_VALUE)) .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup() .addContainerGap(154, Short.MAX_VALUE) .addComponent(saveButton, javax.swing.GroupLayout.PREFERRED_SIZE, 102, javax.swing.GroupLayout.PREFERRED_SIZE) .addGap(144, 144, 144)) .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup() .addContainerGap(140, Short.MAX_VALUE) .addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, 133, javax.swing.GroupLayout.PREFERRED_SIZE) .addGap(127, 127, 127)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addContainerGap() .addComponent(label1, javax.swing.GroupLayout.PREFERRED_SIZE, 25, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(textBox, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) .addComponent(saveButton) .addContainerGap(193, Short.MAX_VALUE)) ); pack(); }// </editor-fold> @SuppressWarnings("static-access") private void saveButtonMousePressed(java.awt.event.MouseEvent evt) { JFileChooser file = new JFileChooser(); file.showSaveDialog(null); String data = file.getSelectedFile().getAbsolutePath(); String text = textBox.getText(); BarcodeGenerator barcodeFactory = new BarcodeGenerator(); try { barcodeFactory.generateBarcode(text, data); } catch (OutputException ex) { Logger.getLogger(uiFrame.class.getName()).log(Level.SEVERE, null, ex); } } /** * @param args the command line arguments */ // Variables declaration - do not modify private javax.swing.JLabel label1; private javax.swing.JButton saveButton; public javax.swing.JTextField textBox; // End of variables declaration } The Main Class (Main.java) package barcode; import javax.swing.JFrame; public class Main { public static void main(String[] args) { JFrame ui = new uiFrame(); ui.pack(); ui.show(); } }

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  • Using charAt in java

    - by ThuL?nå F?rñ?nDö
    This is my assignment: Write a program where the user enters a string, and the program echoes it to the monitor with one character per line: C:\>java LinePerChar Enter a string: Octopus O c t o p u s I have tried, but I'm getting some compilation errors. Here's my code: import java.util.*; class CharactorEcho{ public static void main(String args []){ Scanner sc = new Scanner(System.in); System.out.println("Enter a string :"); try { String inputString = sc.nextLine(); for(int i=0; i < sc.length(); i++) { char c = inputString.charAt(i); System.out.println("" + c); } } catch(IOException e) { } } }

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  • Could not realize media player

    - by user556894
    I am using this code to run avi file using jmf but the error come like "Could not realize media player" and how to open all video format using jmf import javax.media.*; import javax.media.format.*; import java.io.*; import java.util.*; public class Test{ public static void main(String a[]) throws Exception{ CaptureDeviceInfo di = null; Player p = null; Vector deviceList = CaptureDeviceManager.getDeviceList(new AudioFormat("linear", 44100, 16, 2)); if (deviceList.size() > 0){ di = (CaptureDeviceInfo)deviceList.firstElement(); System.out.println((di.getLocator()).toExternalForm()); }else{ System.out.println("Exiting"); System.exit(-1); } try{ p = Manager.createPlayer(di.getLocator()); }catch (IOException e){ System.out.println(e); }catch (NoPlayerException e) { System.out.println(e); } System.out.println("Playing Started"); p.start(); } }

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  • Why function callback of Connection is not handled with Yahoo UI ?

    - by quilovnic
    I use Yahoo UI with Grails (so grailsui) and I try to upload a file with Ajax and get a JSON response from the server : The response is correctly returned by my controller but a popup is displayed to save the file but it's not a file it's a JSON result. My Yahoo Code is : callback = { success: function(o){alert('success');}, failure: function(o){alert('failure');} } YAHOO.util.Connect.asyncRequest('POST', '/my/url', callback); The http response is the JSON result. What's hell is wrong ? Why does I have dialog box to download the file ? Thanks a lot.

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  • Play 2.0 javaToDo tutorial doesn't compile

    - by chsn
    I'm trying to follow the Play2.0 JavaToDO tutorial and for some reason it just doesn't want to work. Have looked through stackoverflow and other online resources, but haven't find an answer to this and it's driving me crazy. Attached code of the Application.java package controllers; import models.Task; import play.data.Form; import play.mvc.Controller; import play.mvc.Result; public class Application extends Controller { static Form<Task> taskForm = form(Task.class); public static Result index() { return redirect(routes.Application.tasks()); } public static Result tasks() { return ok( views.html.index.render(Task.all(), taskForm)); } public static Result newTask() { return TODO; } public static Result deleteTask(Long id) { return TODO; } } Attached code of the Task java package models; import java.util.List; import javax.persistence.Entity; import play.data.Form; import play.data.validation.Constraints.Required; import play.db.ebean.Model.Finder; import play.mvc.Result; import controllers.routes; @Entity public class Task { public Long id; @Required public String label; // search public static Finder<Long,Task> find = new Finder( Long.class, Task.class); // display tasks public static List<Task> all() { return find.all(); } // create task public static void create(Task task) { task.create(task); } // delete task public static void delete(Long id) { find.ref(id).delete(id); // find.ref(id).delete(); } // create new task public static Result newTask() { Form<Task> filledForm = taskForm.bindFromRequest(); if(filledForm.hasErrors()) { return badRequest( views.html.index.render(Task.all(), filledForm) ); } else { Task.create(filledForm.get()); return redirect(routes.Application.tasks()); } } } I get a compile error on Task.java on the line static Form<Task> taskForm = form(Task.class); As I'm working on eclipse (the project is eclipsified before import), it's telling me that taskForm cannot be resolved and it also underlines every play 2 command e.g. "render(), redirect(), bindFromRequest()" asking me to create a method for it. Any ideas how to solve the compilations error and also how to get Eclipse to recognize the play2 commands? EDIT: updated Application.java package controllers; import models.Task; import play.data.Form; import play.mvc.Controller; import play.mvc.Result; public class Application extends Controller { // create new task public static Result newTask() { Form<Task> filledForm = form(Task.class).bindFromRequest(); if(filledForm.hasErrors()) { return badRequest( views.html.index.render(Task.all(), filledForm) ); } else { Task.newTask(filledForm.get()); return redirect(routes.Application.tasks()); } } public static Result index() { return redirect(routes.Application.tasks()); } public static Result tasks() { return ok( views.html.index.render(Task.all(), taskForm)); } public static Result deleteTask(Long id) { return TODO; } } Updated task.java package models; import java.util.List; import javax.persistence.Entity; import play.data.Form; import play.data.validation.Constraints.Required; import play.db.ebean.Model; import play.db.ebean.Model.Finder; import play.mvc.Result; import controllers.routes; @Entity public class Task extends Model { public Long id; @Required public String label; // Define a taskForm static Form<Task> taskForm = form(Task.class); // search public static Finder<Long,Task> find = new Finder( Long.class, Task.class); // display tasks public static List<Task> all() { return find.all(); } // create new task public static Result newTask(Task newTask) { save(task); } // delete task public static void delete(Long id) { find.ref(id).delete(id); // find.ref(id).delete(); } }

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  • Working with EnumSet class in GWT

    - by zenmonkey
    I am having trouble using EnumSet on the client side. I get this runtime error message: java.util.EnumSet.EnumSetImpl is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. Is this is a known issue? Here is what I am doing (basically a hello world app) Service: String echo (EnumSet<Names> name) throws IllegalArgumentException; Client: echoServ.echo (EnumSet.of(Names.JOHN), new AsyncCallback<String>() { ....... }); Shared enum class enum Names { JOHN, NUMAN, OBAMA }

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  • How to get data from dynamically created EditText views and insert it into an array?

    - by Snwspeckle
    So basically what I need my program to do at this point is that when I click the submit button, I need to loop through each dynamic row of the ListView and grab the value in the EditText view and then insert that into an array which I will do further calculations after. Here is my code right now. package com.hello_world; import java.util.ArrayList; import com.hello_world.ByteInputActivity.MyAdapter.ViewHolder; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.util.Log; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnFocusChangeListener; import android.view.View.OnKeyListener; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.TextView; public class ByteInputActivity extends Activity { private ListView myList; private MyAdapter myAdapter; private Integer resQuestions; private Integer indexVal = 0; private View caption; ViewHolder holder; ArrayList<Integer> intArrayList = new ArrayList<Integer>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fieldlist); //Gets number of questions from MainActivity Bundle extras = getIntent().getExtras(); if(extras !=null) { resQuestions = extras.getInt("index"); } myList = (ListView) findViewById(R.id.FieldList); myList.setItemsCanFocus(true); myAdapter = new MyAdapter(); myList.setAdapter(myAdapter); Button submit = (Button) findViewById(R.id.btn_New); submit.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { for (int i = 0; i < myList.getCount() ; i++) { View vListSortOrder; vListSortOrder = myList.getChildAt(i); String temp = holder.caption.getText().toString(); Log.e("VALUES", "" +temp); } } }); } public class MyAdapter extends BaseAdapter { private LayoutInflater mInflater; public ArrayList myItems = new ArrayList(); public MyAdapter() { mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); for (int i = 0; i < resQuestions; i++) { ListItem listItem = new ListItem(); listItem.caption = "Index " + i; listItem.indexText = "Index " + i; myItems.add(listItem); indexVal += 1; } notifyDataSetChanged(); } public int getCount() { return myItems.size(); } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { if (convertView == null) { holder = new ViewHolder(); convertView = mInflater.inflate(R.layout.item, null); holder.indexText = (TextView) convertView .findViewById(R.id.textView1); holder.caption = (EditText) convertView .findViewById(R.id.ItemCaption); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } //Fill EditText with the value you have in data source holder.caption.setText(""); holder.caption.setId(position); holder.indexText.setText("Index " + position); holder.indexText.setId(position); //we need to update adapter once we finish with editing holder.caption.setOnFocusChangeListener(new OnFocusChangeListener() { public void onFocusChange(View v, boolean hasFocus) { if (!hasFocus){ final int position = v.getId(); final EditText Caption = (EditText) v; myItems.set(position, Caption.getText().toString()); } } }); return convertView; } class ViewHolder { EditText caption; TextView indexText; } class ListItem { String caption; String indexText; } } }

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  • I have applied a check for not allowing alphabets.But its not working.....

    - by bhavna raghuvanshi
    import java.util.Scanner; public class Main extends Hashmap{ public static void main(String[] args) { Hashmap hm = new Hashmap(); int x=0; Scanner input = new Scanner(System.in); do{ System.out.print("Enter any integer value between 1 to 12: "); x = input.nextInt(); }while(x<=0 || x>12); Scanner sc = new Scanner(System.in); //int number; do { while (!sc.hasNextInt()) { System.out.println("That's not a number!"); sc.next(); } x = sc.nextInt(); }while(x>=0); String month = hm.getEntry(x); System.out.println(month); } } here I need to restrict user from entering an alphabet.But its not working. pls help...

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  • Why people are so afraid of using clone() (on collection and JDK classes) ?

    - by Bozho
    A number of times I've argued that using clone() isn't such a bad practice. Yes, I know the arguments. Bloch said it's bad. He indeed did, but he said that implementing clone() is bad. Using clone on the other hand, especially if it is implemented correctly by a trusted library, such as the JDK, is OK. Just yesterday I had a discussion about an answer of mine that merely suggests that using clone() for ArrayList is OK (and got no upvotes for that reason, I guess). If we look at the @author of ArrayList, we can see a familiar name - Josh Bloch. So clone() on ArrayList (and other collections) is perfectly fine. (Just look at the implementation). Same goes for Calendar and perhaps most of the java.lang and java.util classes. So, give me a reason why not to use clone() with JDK classes?

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  • Search Oracle date type column with hibernate, seach by everything in that day - ignore the time.

    - by Setori
    hi there <property name="batchCreatedDate" type="java.util.Date"> <meta attribute="field-description">batch create date</meta> <column name="BATCH_CREATED_DATE" length="7" not-null="true" /> </property> table column type is BATCH_CREATED_DATE DATE NOT NULL With the data in that date column being similar to this '2010-05-13 14:56:36.0' now I want to search for all items within the 24 hours of 2010-05-13, currently my call only returns all items with date "2010-05-13 14:56:36.0" exactly. What would my HQL statement look like to hand this kind of scenario? Thank you so much

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  • Error showing is NullPointerException [duplicate]

    - by user3659612
    This question already has an answer here: How to check a string against null in java? 11 answers I was trying to code a wifi scanner which does 20 scans but it shows NullPointerException at if(bssid[j].equals(null)){ My code is slightly huge package com.example.scanner; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStreamWriter; import java.text.SimpleDateFormat; import java.util.Date; import java.util.List; import android.annotation.SuppressLint; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.net.wifi.ScanResult; import android.net.wifi.WifiInfo; import android.net.wifi.WifiManager; import android.os.Bundle; import android.os.Environment; import android.support.v7.app.ActionBarActivity; import android.view.Menu; import android.view.View; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ListView; import android.widget.Toast; public class MainActivity extends ActionBarActivity { WifiManager wifi; WifiScanReceiver wifireciever; WifiInfo info; Button scan, save; List<ScanResult> wifilist; ListView list; String wifis[]; String name; String[] ssid = new String[100]; String[] bssid = new String[100]; int[] lvl = new int[100]; int[] count = new int[100]; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fragment_main); list=(ListView)findViewById(R.id.listView1); scan=(Button)findViewById(R.id.button1); save=(Button)findViewById(R.id.button2); scan.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub wifi=(WifiManager)getSystemService(Context.WIFI_SERVICE); if (wifi.isWifiEnabled()==false){ wifi.setWifiEnabled(true); } wifireciever = new WifiScanReceiver(); for (int i=0;i<20;i++){ registerReceiver(wifireciever, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)); wifi.startScan(); if (i==19){ Toast.makeText(getBaseContext(), "Scan Finish", Toast.LENGTH_LONG).show(); } } } }); save.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub savedata(); } }); } protected void savedata() { // TODO Auto-generated method stub try { File sdcard = Environment.getExternalStorageDirectory(); File directory = new File(sdcard.getAbsolutePath() + "/WIFI_RESULT"); directory.mkdirs(); name = new SimpleDateFormat("yyyy-MM-dd HH mm ss").format(new Date()); File file = new File(directory,name + "wifi_data.txt"); FileOutputStream fou = new FileOutputStream(file); OutputStreamWriter osw = new OutputStreamWriter(fou); try { for (int i =0; i < list.getCount(); i++){ osw.append(list.getItemAtPosition(i).toString()); } osw.flush(); osw.close(); Toast.makeText(getBaseContext(), "Saved", Toast.LENGTH_LONG).show(); } catch (IOException e){ e.printStackTrace(); } } catch (FileNotFoundException e){ e.printStackTrace(); } } class WifiScanReceiver extends BroadcastReceiver { @SuppressLint("UseValueOf") public void onReceive(Context c, Intent intent) { int a =0; wifi.startScan(); List<ScanResult> wifilist = wifi.getScanResults(); if (a<wifilist.size()){ a=wifilist.size(); } for(int j=0;j<wifilist.size();j++){ if(bssid[j].equals(null)){ ssid[j] = wifilist.get(j).SSID.toString(); bssid[j] = wifilist.get(j).BSSID.toString(); lvl[j] = wifilist.get(j).level; count[j]++; } else if (bssid[j].equals(wifilist.get(j).BSSID.toString())){ lvl[j] = lvl[j] + wifilist.get(j).level; count[j]++; } } wifis = new String[a]; for (int i =0; i<a; i++){ wifis[i] = ("\n" + ssid[i] + "\n AP Address" + bssid[i] + "\n Signal Strength:" + lvl[i]/count[i]).toString(); } list.setAdapter(new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1,wifis)); } } protected void onDestroy() { unregisterReceiver(wifireciever); super.onPause(); } protected void onResume() { registerReceiver(wifireciever, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)); super.onResume(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } } NullPointerException at that point mean my array bssid isn't initialize. So I just want to know how to initialize it in main activity so that I can use that string bssid anywhere.

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  • Java: design problem with private-final-int-value and empty constructor

    - by HH
    $ javac InitInt.java InitInt.java:7: variable right might not have been initialized InitInt(){} ^ 1 error $ cat InitInt.java import java.util.*; import java.io.*; public class InitInt { private final int right; //DUE to new Klowledge: Design Problem //I think having an empty constructor like this // is an design problem, shall I remove it? What do you think? // When to use an empty constructor? InitInt(){} public static void main(String[] args) { InitInt test = new InitInt(); System.out.println(test.getRight()); } public int getRight(){return right;} } Initialization problem with Constructor InitInt{ // Still the error, "may not be initialized" // How to initialise it? if(snippetBuilder.length()>(charwisePos+25)){ right=charwisePos+25; }else{ right=snippetBuilder.length()-1; } }

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