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  • Using prepared statements with JDBCTemplate

    - by Bernhard V
    Hi. I'm using the Jdbc template and want to read from the database using prepared statements. I iterate over many lines in a csv file and on every line I execute some sql select queries with it's values. Now I want to speed up my reading from the database but I just can't get the Jdbc template to work with prepared statements. Actually I even don't know how to do it. There is the PreparedStatementCreator and the PreparedStatementCreator. As in this example both of them are created with anonymous inner classes. But inside the PreparedStatementCreator class I don't have access to the values I want to set in the prepared statement. Since I'm iterating through a csv file I can't hard code them as a String because I don't know them. I also can't pass them to the PreparedStatementCreator because there are no arguments for the constructor. I was used to the creation of prepared statements being fairly simple. Something like PreparedStatement updateSales = con.prepareStatement( "UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ? "); updateSales.setInt(1, 75); updateSales.setString(2, "Colombian"); updateSales.executeUpdate(): as in the Java tutorial. Your help would be very appreciated.

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  • How to use XPath to filter elements by TextContent? get parent by axis?

    - by Michael Mao
    Hi all: I've found a similar question on SO, however, that seems not exactly what I wanna achieve: Say, this is a sample XML file: <root> <item> <id isInStock="true">10001</id> <category>Loose Balloon</category> </item> <item> <id isInStock="true">10001</id> <category>Bouquet Balloon</category> </item> <item> <id isInStock="true">10001</id> <category>Loose Balloon</category> </item> </root> If I wanna get a "filtered" subset of the item elements from this XML, how could I use an XPath expression to directly address that? XPathExpression expr = xpath.compile("/root/item/category/text()"); I now know this would evaluate to be the collection of all the TextContent from the categories, however, that means I have to use a collection to store the values, then iterate, then go back to grab other related info such as the item id again. Another question is : how could I refer to the parent node properly? Say, this xpath expression would get me the collection of all the id nodes, right? But what I want is the collection of item nodes: XPathExpression expr = xpath.compile("/root/item/id[@isInStock='true']"); I know I should use the "parent" axis to refer to that, but I just cannot make it right... Is there a better way of doing this sort of thing? Learning the w3cschools tutorials now... Sorry I am new to XPath in Java, and thanks a lot in advance.

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  • Why is it a bad practice to call System.gc?

    - by zneak
    After answering to a question about how to force-free objects in Java (the guy was clearing a 1.5GB HashMap) with System.gc(), I've been told it's a bad practice to call System.gc() manually, but the comments seemed mitigated about it. So much that no one dared to upvote it, nor downvote it. I've been told there it's a bad practice, but then I've also been told garbage collector runs don't systematically stop the world anymore, and that it could also be only seen as a hint, so I'm kind of at loss. I do understand that usually the JVM knows better than you when it needs to reclaim memory. I also understand that worrying about a few kilobytes of data is silly. And I also understand that even megabytes of data isn't what it was a few years back. But still, 1.5 gigabyte? And you know there's like 1.5 GB of data hanging around in memory; it's not like it's a shot in the dark. Is System.gc() systematically bad, or is there some point at which it becomes okay? So the question is actually double: Why is it or not a bad practice to call System.gc()? Is it really a hint under certain implementations, or is it always a full collection cycle? Are there really garbage collector implementations that can do their work without stopping the world? Please shed some light over the various assertions people have made. Where's the threshold? Is it never a good idea to call System.gc(), or are there times when it's acceptable? If any, what are those times?

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  • executing stored procedure from Spring-Hibernate using Annotations

    - by HanuAthena
    I'm trying to execute a simple stored procedure with Spring/Hibernate using Annotations. Here are my code snippets: DAO class: public class UserDAO extends HibernateDaoSupport { public List selectUsers(final String eid){ return (List) getHibernateTemplate().execute(new HibernateCallback() { public Object doInHibernate(Session session) throws HibernateException, SQLException { Query q = session.getNamedQuery("SP_APPL_USER"); System.out.println(q); q.setString("eid", eid); return q.list(); } }); } } my entity class: @Entity @Table(name = "APPL_USER") @Inheritance(strategy = InheritanceType.SINGLE_TABLE) @DiscriminatorFormula(value = "SUBSCRIBER_IND") @DiscriminatorValue("N") @NamedQuery(name = "req.all", query = "select n from Requestor n") @org.hibernate.annotations.NamedNativeQuery(name = "SP_APPL_USER", query = "call SP_APPL_USER(?, :eid)", callable = true, readOnly = true, resultClass = Requestor.class) public class Requestor { @Id @Column(name = "EMPL_ID") public String getEmpid() { return empid; } public void setEmpid(String empid) { this.empid = empid; } @Column(name = "EMPL_FRST_NM") public String getFirstname() { return firstname; } ... } public class Test { public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext( "applicationContext.xml"); APFUser user = (APFUser)ctx.getBean("apfUser"); List selectUsers = user.getUserDAO().selectUsers("EMP456"); System.out.println(selectUsers); } } and the stored procedure: create or replace PROCEDURE SP_APPL_USER (p_cursor out sys_refcursor, eid in varchar2) as empId varchar2(8); fname varchar2(50); lname varchar2(50); begin empId := null; fname := null; lname := null; open p_cursor for select l.EMPL_ID, l.EMPL_FRST_NM, l.EMPL_LST_NM into empId, fname, lname from APPL_USER l where l.EMPL_ID = eid; end; If i enter invalid EID, its returning empty list which is OK. But when record is there, following exception is thrown: Exception in thread "main" org.springframework.jdbc.BadSqlGrammarException: Hibernate operation: could not execute query; bad SQL grammar [call SP_APPL_USER(?, ?)]; nested exception is java.sql.SQLException: Invalid column name Do I need to modify the entity(Requestor.class) ? How will the REFCURSOR be converted to the List? The stored procedure is expected to return more than one record.

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  • Covariance and Contravariance type inference in C# 4.0

    - by devoured elysium
    When we define our interfaces in C# 4.0, we are allowed to mark each of the generic parameters as in or out. If we try to set a generic parameter as out and that'd lead to a problem, the compiler raises an error, not allowing us to do that. Question: If the compiler has ways of inferring what are valid uses for both covariance (out) and contravariance(in), why do we have to mark interfaces as such? Wouldn't it be enough to just let us define the interfaces as we always did, and when we tried to use them in our client code, raise an error if we tried to use them in an un-safe way? Example: interface MyInterface<out T> { T abracadabra(); } //works OK interface MyInterface2<in T> { T abracadabra(); } //compiler raises an error. //This makes me think that the compiler is cappable //of understanding what situations might generate //run-time problems and then prohibits them. Also, isn't it what Java does in the same situation? From what I recall, you just do something like IMyInterface<? extends whatever> myInterface; //covariance IMyInterface<? super whatever> myInterface2; //contravariance Or am I mixing things? Thanks

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  • Log4j Relative Path to Tomcat7 Log Directory File Not Found

    - by Nik
    I have this log4j XML file: <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/"> <appender name="gemFile" class="org.apache.log4j.RollingFileAppender"> <param name="File" value="file:${catalina.home}/logs/GEM.log" /> <param name="MaxBackupIndex" value="5" /> <param name="MaxFileSize" value="3MB" /> <param name="Append" value="true" /> <layout class="org.apache.log4j.PatternLayout"> <param name="ConversionPattern" value="[%t] %d{yyyy-MM-dd HH:mm:ss.SSS} %-5p %c{1} - %m%n" /> </layout> </appender> <root> <priority value ="info" /> <appender-ref ref="gemFile" /> </root> </log4j:configuration> ${catalina.home} resolves to C:\Apps\Apache\Tomcat7. When I deploy my WAR file, I get log4j:ERROR setFile(null,true) call failed. java.io.FileNotFoundException: file:C:\Apps\Apache\Tomcat7\logs\GEM.log (The filename, directory name, or volume label syntax is incorrect) stack trace... It is true that the log file does not exist (the folder structure does), but if I set the file directly to that path (<param name="File" value="C:/Apps/Apache/Tomcat7/logs/GEM.log" />) it works fine. Why can't I use the replacement string?

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  • Serialization Performance and Google Android

    - by Jomanscool2
    I'm looking for advice to speed up serialization performance, specifically when using the Google Android. For a project I am working on, I am trying to relay a couple hundred objects from a server to the Android app, and am going through various stages to get the performance I need. First I tried a terrible XML parser that I hacked together using Scanner specifically for this project, and that caused unbelievably slow performance when loading the objects (~5 minutes for a 300KB file). I then moved away from that and made my classes implement Serializable and wrote the ArrayList of objects I had to a file. Reading that file into the objects the Android, with the file already downloaded mind you, was taking ~15-30 seconds for the ~100KB serialized file. I still find this completely unacceptable for an Android app, as my app requires loading the data when starting the application. I have read briefly about Externalizable and how it can increase performance, but I am not sure as to how one implements it with nested classes. Right now, I am trying to store an ArrayList of the following class, with the nested classes below it. public class MealMenu implements Serializable{ private String commonsName; private long startMillis, endMillis, modMillis; private ArrayList<Venue> venues; private String mealName; } And the Venue class: public class Venue implements Serializable{ private String name; private ArrayList<FoodItem> foodItems; } And the FoodItem class: public class FoodItem implements Serializable{ private String name; private boolean vegan; private boolean vegetarian; } IF Externalizable is the way to go to increase performance, is there any information as to how java calls the methods in the objects when you try to write it out? I am not sure if I need to implement it in the parent class, nor how I would go about serializing the nested objects within each object.

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  • How to force an HTML JLabel in a JTree to resize when the font changes

    - by Mike
    I'm updating a Java Swing application to support the user switching the app's font from normal size to a larger size (so the user can switch between the two sizes at runtime). One problem I'm having is with a JTree that uses HTML for the tree nodes to underline the text in some nodes (the HTML is just embedded in the JLabel of each tree node). One extra thing to know about the nodes is that they're a custom component, adding a JCheckBox in front of each JLabel. The problem is that once the JTree is visible, increasing the font size causes the nodes (containing underlined text) to not resize. The HTML for those nodes seems to prevent the node from becoming wider, so when the font changes, the text becomes truncated. I think my options are to either: 1) use another approach to make the text underlined, since removing the HTML from the JLabel causes it to resize properly when the font size changes, or 2) keep the HTML formatting and somehow force the JTree/JLabels to resize when the font size is updated (possibly by firing a property change event?). The code already calls SwingUtilities.updateComponentTreeUI() on the parent JFrame when the font size gets updated. Any help would be greatly appreciated. Thanks in advance! -Mike

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  • Connect two client sockets

    - by Hernán Eche
    Good morning, let's say Java has two kind of sockets... server sockets "ServerSocket" client sockets or just "Socket" ////so Simple ! Imagine the situation of two processes: X Client <-- Y Server The server process Y : has a "ServerSocket", that is listening to a TCP port The client process X : send a connection request through a -client type- "Socket" X ////so Simple ! then the accept() method (in server Y) returns a new client type "Socket", when it occurs, great the two Sockets get "interconected", so the -client socket- in client process, is connected with the -client socket- in the server process then (reading/writing in socket X is like reading/writing in socket Y, and viceversa. ) TWO CLIENT SOCKETS GET INTERCONECTED!! ////so Simple ! BUT... (there is always a But..) What if I create the two CLIENT sockets in same process, and I want to get them "interconected" ? ////mmm Complex =(... even posible? Let's say how to have TWO CLIENT SOCKETS GET INTERCONECTED WITHOUT using an intermediate ServerSocket ? I 've solved it.. by creating two threads for continuously reading A and writing B, and other for reading B and writng A... but I think could be a better way..(or should!) (Those world-energy-consuming threads are not necessary with the client-server aproach) Any help or advice would be appreciated!! Thanks

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  • JPA - Setting entity class property from calculated column?

    - by growse
    I'm just getting to grips with JPA in a simple Java web app running on Glassfish 3 (Persistence provider is EclipseLink). So far, I'm really liking it (bugs in netbeans/glassfish interaction aside) but there's a thing that I want to be able to do that I'm not sure how to do. I've got an entity class (Article) that's mapped to a database table (article). I'm trying to do a query on the database that returns a calculated column, but I can't figure out how to set up a property of the Article class so that the property gets filled by the column value when I call the query. If I do a regular "select id,title,body from article" query, I get a list of Article objects fine, with the id, title and body properties filled. This works fine. However, if I do the below: Query q = em.createNativeQuery("select id,title,shorttitle,datestamp,body,true as published, ts_headline(body,q,'ShortWord=0') as headline, type from articles,to_tsquery('english',?) as q where idxfti @@ q order by ts_rank(idxfti,q) desc",Article.class); (this is a fulltext search using tsearch2 on Postgres - it's a db-specific function, so I'm using a NativeQuery) You can see I'm fetching a calculated column, called headline. How do I add a headline property to my Article class so that it gets populated by this query? So far, I've tried setting it to be @Transient, but that just ends up with it being null all the time.

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  • Android: NullPointerException error in getting data in database

    - by Gil Viernes Marcelo
    This what happens in the system. 1. Admin login this is in other activity but i will not post it coz it has nothing to do with this (no problem) 2. Register user in system (using database no problem) 3. Click add user button (where existing user who register must display its name in ListView) Problem: When I click adduser to see if the system registered the user, it force close. CurrentUser.java package com.example.istronggyminstructor; import java.util.ArrayList; import android.os.Bundle; import android.app.Activity; import android.content.Context; import android.content.Intent; import android.database.Cursor; import android.view.Gravity; import android.view.LayoutInflater; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewGroup; import android.view.ViewGroup.LayoutParams; import android.view.WindowManager; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.FrameLayout; import android.widget.ListView; import android.widget.PopupWindow; import android.widget.TextView; import android.widget.Toast; import java.util.ArrayList; import java.util.List; import java.util.Random; import com.example.istronggyminstructor.registeredUserList.Users; import android.content.ContentValues; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; public class CurrentUsers extends Activity { private Button register; private Button adduser; EditText getusertext, getpass, getweight, textdisp; View popupview, popupview2; public static ArrayList<String> ArrayofName = new ArrayList<String>(); protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_current_users); register = (Button) findViewById(R.id.regbut); adduser = (Button) findViewById(R.id.addbut); register.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { LayoutInflater inflator = (LayoutInflater) getBaseContext() .getSystemService(LAYOUT_INFLATER_SERVICE); popupview = inflator.inflate(R.layout.popup, null); final PopupWindow popupWindow = new PopupWindow(popupview, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); popupWindow.showAtLocation(popupview, Gravity.CENTER, 0, 0); popupWindow.setFocusable(true); popupWindow.update(); Button dismissbtn = (Button) popupview.findViewById(R.id.close); dismissbtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { popupWindow.dismiss(); } }); popupWindow.showAsDropDown(register, 50, -30); } }); //Thread.setDefaultUncaughtExceptionHandler(new forceclose(this)); } public void registerUser(View v) { EditText username = (EditText) popupview.findViewById(R.id.usertext); EditText password = (EditText) popupview .findViewById(R.id.passwordtext); EditText weight = (EditText) popupview.findViewById(R.id.weight); String getUsername = username.getText().toString(); String getPassword = password.getText().toString(); String getWeight = weight.getText().toString(); dataHandler dbHandler = new dataHandler(this, null, null, 1); Users user = new Users(getUsername, getPassword, Integer.parseInt(getWeight)); dbHandler.addUsers(user); Toast.makeText(getApplicationContext(), "Registering...", Toast.LENGTH_SHORT).show(); } public void onClick_addUser(View v) { LayoutInflater inflator = (LayoutInflater) getBaseContext() .getSystemService(LAYOUT_INFLATER_SERVICE); popupview2 = inflator.inflate(R.layout.popup2, null); final PopupWindow popupWindow = new PopupWindow(popupview2, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); popupWindow.showAtLocation(popupview2, Gravity.CENTER, 0, -10); popupWindow.setFocusable(true); popupWindow.update(); Button dismissbtn = (Button) popupview2.findViewById(R.id.close2); dismissbtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { popupWindow.dismiss(); } }); popupWindow.showAsDropDown(register, 50, -30); dataHandler dbHandler = new dataHandler(this, null, null, 1); dbHandler.getAllUsers(); ListView list = (ListView)findViewById(R.layout.popup2); ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, ArrayofName); list.setAdapter(adapter); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.current_users, menu); return true; } } registeredUserList.java package com.example.istronggyminstructor; public class registeredUserList { public static class Users { private static int _id; private static String _users; private static String _password; private static int _weight; private static String[] _workoutlists; private static int _score; public Users() { } public Users(String username, String password, int weight) { _users = username; _password = password; _weight = weight; } public int getId() { return _id; } public static void setId(int id) { _id = id; } public String getUsers() { return _users; } public static void setUsers(String users) { _users = users; } public String getPassword(){ return _password; } public void setPassword(String password){ _password = password; } public int getWeight(){ return _weight; } public static void setWeight(int weight){ _weight = weight; } public String[] getWorkoutLists(){ return _workoutlists; } public void setWorkoutLists(String[] workoutlists){ _workoutlists = workoutlists; } public int score(){ return _score; } public void score(int score){ _score = score; } } } dataHandler.java package com.example.istronggyminstructor; import java.util.ArrayList; import java.util.List; import com.example.istronggyminstructor.registeredUserList.Users; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; public class dataHandler extends SQLiteOpenHelper { private static final int DATABASE_VERSION = 1; private static final String DATABASE_NAME = "userInfo.db"; public static final String TABLE_USERINFO = "user"; public static final String COLUMN_ID = "_id"; public static final String COLUMN_USERNAME = "username"; public static final String COLUMN_PASSWORD = "password"; public static final String COLUMN_WEIGHT = "weight"; public dataHandler(Context context, String name, CursorFactory factory, int version) { super(context, DATABASE_NAME, factory, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { String CREATE_USER_TABLE = "CREATE TABLE " + TABLE_USERINFO + " (" + COLUMN_ID + " INTEGER PRIMARY KEY, " + COLUMN_USERNAME + " TEXT," + COLUMN_PASSWORD + " TEXT, " + COLUMN_WEIGHT + " INTEGER " + ");"; db.execSQL(CREATE_USER_TABLE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS " + TABLE_USERINFO); onCreate(db); } public void addUsers(Users user) { ContentValues values = new ContentValues(); values.put(COLUMN_USERNAME, user.getUsers()); values.put(COLUMN_PASSWORD, user.getPassword()); values.put(COLUMN_WEIGHT, user.getWeight()); SQLiteDatabase db = this.getWritableDatabase(); db.insert(TABLE_USERINFO, null, values); db.close(); } public Users findUsers(String username) { String query = "Select * FROM " + TABLE_USERINFO + " WHERE " + COLUMN_USERNAME + " = \"" + username + "\""; SQLiteDatabase db = this.getWritableDatabase(); Cursor cursor = db.rawQuery(query, null); Users user = new Users(); if (cursor.moveToFirst()) { cursor.moveToFirst(); Users.setUsers(cursor.getString(1)); //Users.setWeight(Integer.parseInt(cursor.getString(3))); not yet needed cursor.close(); } else { user = null; } db.close(); return user; } public List<Users> getAllUsers(){ List<Users> user = new ArrayList(); String selectQuery = "SELECT * FROM " + TABLE_USERINFO; SQLiteDatabase db = this.getWritableDatabase(); Cursor cursor = db.rawQuery(selectQuery, null); if (cursor.moveToFirst()) { do { Users users = new Users(); users.setUsers(cursor.getString(1)); String name = cursor.getString(1); CurrentUsers.ArrayofName.add(name); // Adding contact to list user.add(users); } while (cursor.moveToNext()); } // return user list return user; } public boolean deleteUsers(String username) { boolean result = false; String query = "Select * FROM " + TABLE_USERINFO + " WHERE " + COLUMN_USERNAME + " = \"" + username + "\""; SQLiteDatabase db = this.getWritableDatabase(); Cursor cursor = db.rawQuery(query, null); Users user = new Users(); if (cursor.moveToFirst()) { Users.setId(Integer.parseInt(cursor.getString(0))); db.delete(TABLE_USERINFO, COLUMN_ID + " = ?", new String[] { String.valueOf(user.getId()) }); cursor.close(); result = true; } db.close(); return result; } } Logcat 08-20 03:23:23.293: E/AndroidRuntime(16363): FATAL EXCEPTION: main 08-20 03:23:23.293: E/AndroidRuntime(16363): java.lang.IllegalStateException: Could not execute method of the activity 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.view.View$1.onClick(View.java:3599) 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.view.View.performClick(View.java:4204) 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.view.View$PerformClick.run(View.java:17355) 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.os.Handler.handleCallback(Handler.java:725) 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.os.Handler.dispatchMessage(Handler.java:92) 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.os.Looper.loop(Looper.java:137) 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.app.ActivityThread.main(ActivityThread.java:5041) 08-20 03:23:23.293: E/AndroidRuntime(16363): at java.lang.reflect.Method.invokeNative(Native Method) 08-20 03:23:23.293: E/AndroidRuntime(16363): at java.lang.reflect.Method.invoke(Method.java:511) 08-20 03:23:23.293: E/AndroidRuntime(16363): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 08-20 03:23:23.293: E/AndroidRuntime(16363): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 08-20 03:23:23.293: E/AndroidRuntime(16363): at dalvik.system.NativeStart.main(Native Method) 08-20 03:23:23.293: E/AndroidRuntime(16363): Caused by: java.lang.reflect.InvocationTargetException 08-20 03:23:23.293: E/AndroidRuntime(16363): at java.lang.reflect.Method.invokeNative(Native Method) 08-20 03:23:23.293: E/AndroidRuntime(16363): at java.lang.reflect.Method.invoke(Method.java:511) 08-20 03:23:23.293: E/AndroidRuntime(16363): at android.view.View$1.onClick(View.java:3594) 08-20 03:23:23.293: E/AndroidRuntime(16363): ... 11 more 08-20 03:23:23.293: E/AndroidRuntime(16363): Caused by: java.lang.NullPointerException 08-20 03:23:23.293: E/AndroidRuntime(16363): at com.example.istronggyminstructor.CurrentUsers.onClick_addUser(CurrentUsers.java:118) 08-20 03:23:23.293: E/AndroidRuntime(16363): ... 14 more

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  • Incremental Timer

    - by Donal Rafferty
    I'm currently using a Timer and TimerTask to perform some work every 30 seconds. My problem is that after each time I do this work I want to increment the interval time of the Timer. So for example it starts off with 30 seconds between the timer firing but I want to add 10 seconds to the interval then so that the next time the Timer takes 40 seconds before it fires. Here is my current code: public void StartScanning() { scanTask = new TimerTask() { public void run() { handler.post(new Runnable() { public void run() { wifiManager.startScan(); scanCount++; if(SCAN_INTERVAL_TIME <= SCAN_MAX_INTERVAL){ SCAN_INTERVAL_TIME = SCAN_INTERVAL_TIME + SCAN_INCREASE_INTERVAL; t.schedule(scanTask, 0, SCAN_INTERVAL_TIME); } } }); }}; Log.d("SCAN_INTERVAL_TIME ** ", "SCAN_INTERVAL_TIME ** = " + SCAN_INTERVAL_TIME); t.schedule(scanTask, 0, SCAN_INTERVAL_TIME); } But the above gives the following error: 05-26 11:48:02.472: ERROR/AndroidRuntime(4210): java.lang.IllegalStateException: TimerTask is scheduled already Calling cancel or purge doesn't help. So I was wondering if anyone can help me find a solution? Is a timer even the right way to approach this?

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  • NetBeans Tips and Tricks

    - by cdmckay
    I just saw an Eclipse tips & tricks post and was wondering if anyone had any tips & tricks for my IDE of choice: NetBeans. Here's a few I know and find to be useful: Removing a package: After you remove a package in NetBeans, it sticks around as a grayed-out package in your Project view. To get rid of that, switch to Files view and delete the directory. Alt-Insert (in Windows) opens up a Generate submenu at your cursor. A nice shortcut for quickly generating getters/setters (among other things). Selecting a chunk of code, right-clicking and then clicking "Refactor Introduce Method" will have NetBeans introduce a method, complete with arguments and return value. Of course you have to make sure the chunk of code only has one return value. Sometimes when you run a build and it crashes, the Java window sticks around at the bottom. I used to just click X until Windows let me End Task, but there's a nicer way to get rid of them. Click "Run Stop Build/Run" and NetBeans will close the window for you. It'll even let you close multiple applications at once. These may seem obvious to grizzled NetBeans developers, but I thought they might be useful for NetBeans newbs like me. Anyone else have any tips/tricks to share? Here are some from the comments: NetBeans allows for code templates. You can even add yours on the Code Templates tab under the Editor settings on the Options window. Some examples: Type sout and hit the tab key as a shorcut for System.out.println("") Type psvm and hit the tab key as a shorcut for public static void main(String args[]) {} Ctrl Shift C: Comments out the selected block of code. Alt Shift F: Formats the selected block of code. Ctrl E: Deletes current line. Ctrl Shift I: Fixes your imports, handy if you've just written a piece of code that needs a lot of packages imported.

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  • Cannot find symbol - variable

    - by Ben Garside
    I'm new to Java, and I'm trying to get user input, store each line of input as a variable and then return each value so that it can be passed on somewhere else. When I try and compile it is telling me that it can't find the variable magnitude. I'm assuming it won't find the others either. I'm guessing that this is because I've declare the variables inside of the "try" but don't know how to get it so that the return statement accepts them. Code is as follows: public Earthquake userAddEarthquake() { Scanner scanner = new Scanner(System.in); try{ // convert the string read from the scanner into Integer type System.out.println("Please Enter An Earthquake Magnitude: "); Double magnitude = Double.parseDouble(scanner.nextLine()); System.out.println("Please Enter The Earthquakes Latitude Position: "); scanner = new Scanner(System.in); Double positionLatitude = Double.parseDouble(scanner.nextLine()); System.out.print("Please Enter The Earthquakes Longitude Position: "); scanner = new Scanner(System.in); Double positionLongitude = Double.parseDouble(scanner.nextLine()); System.out.print("Please Enter The Year That The Earthquake Occured: "); scanner = new Scanner(System.in); int year = Integer.parseInt(scanner.nextLine()); System.out.println("Magnitude = " + magnitude); } catch(NumberFormatException ne){ System.out.println("Invalid Input"); } finally{ scanner.close(); } return new Earthquake(magnitude, positionLatitude, positionLongitude, year); }

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  • JAX-WS client with AXIS server; namespace problem?

    - by Jarno
    I'm having a problem related to JAX-WS and AXIS. JAX-WS (2.1.7) as a client, Axis (1.4.x) as server. Everything works OK, but the response can't be read to Java. Response: <?xml version="1.0" encoding="UTF-8"?> <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <soapenv:Body> <ns1:myserviceResponse soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:ns1="http://my/service"> <ns1:myserviceReturn xsi:type="xsd:string">responsestring</ns1:myserviceReturn> </ns1:myserviceResponse> </soapenv:Body> </soapenv:Envelope> The problem is that if "ns1:"-namespace declaration is removed from myserviceReturn, JAX-WS is able to return else than null. Does anyone have a clue how to force JAX-WS to ignore namespaces, how to modify SOAP response manually to exclude "ns1", or other ideas for this kind of problem? Any help is appreciated!!!

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  • JSP Document/JSPX: what determines how tabs/space/linebreaks are removed in the output?

    - by NoozNooz42
    I've got a "JSP Document" ("JSP in XML") nicely formatted and when the webpage is generated and sent to the user, some linebreaks are removed. Now the really weird part: apparently the "main" .jsp always gets all its linebreak removed but for any subsequent .jsp included from the main .jsp, linebreaks seems to be randomly removed (some are there, others aren't). For example, if I'm looking at the webpage served from Firefox and ask to "view source", I get to see what is generated. So, what determines when/how linebreaks are kept/removed? This is just an example I made up... Can you force a .jsp to serve this: <body><div id="page"><div id="header"><div class="title">... or this: <body> <div id="page"> <div id="header"> <div class="title">... ? I take it that linebreaks are removed to save on bandwidth, but what if I want to keep them? And what if I want to keep the same XML indentation as in my .jsp file? Is this doable? EDIT Following skaffman's advice, I took a look at the generated .java files and the "main" one doesn't have lots of out.write but not a single one writing tabs nor newlines. Contrary to that file, all the ones that I'm including from that main .jsp have lots of lines like: out.write("\t...\n"); So I guess my question stays exactly the same: what determines how tabs/space/linebreaks are included/removed in the output?

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  • Mocking inter-method dependencies

    - by Zecrates
    I've recently started using mock objects in my tests, but I'm still very inexperienced with them and unsure of how to use them in some cases. At the moment I'm struggling with how to mock inter-method dependencies (calling method A has an effect on the results of method B), and whether it should even be mocked (in the sense of using a mocking framework) at all? Take for example a Java Iterator? It is easy enough to mock the next() call to return the correct values, but how do I mock hasNext(), which depends on how many times next() has been called? Currently I'm using a List.Iterator as I could find no way to properly mock one. Does Martin Fowler's distinction between mocks and stubs come into play here? Should I rather write my own IteratorMock? Also consider the following example. The method to be tested calls mockObject.setX() and later on mockObject.getX(). Is there any way that I can create such a mock (without writing my own) which will allow the returned value of getX to depend on what was passed to setX?

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  • HashMap key problems

    - by Peterdk
    I'm profiling some old java code and it appears that my caching of values using a static HashMap and a access method does not work. Caching code (a bit abstracted): static HashMap<Key, Value> cache = new HashMap<Key, Value>(); public static Value getValue(Key key){ System.out.println("cache size="+ cache.size()); if (cache.containsKey(key)) { System.out.println("cache hit"); return cache.get(key); } else { System.out.println("no cache hit"); Value value = calcValue(); cache.put(key, value); return value; } } Profiling code: for (int i = 0; i < 100; i++) { getValue(new Key()); } Result output: cache size=0 no cache hit (..) cache size=99 no cache hit It looked like a standard error in Key's hashing code or equals code. However: new Key().hashcode == new Key().hashcode // TRUE new Key().equals(new Key()) // TRUE What's especially weird is that cache.put(key, value) just adds another value to the hashmap, instead of replacing the current one. So, I don't really get what's going on here. Am I doing something wrong?

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  • Why ClassCastException on JMS ConnectionFactory lookup in JNDI?

    - by Derek Mahar
    What might be the cause of the following ClassCastException in a standalone JMS client application when it attempts to retrieve a connection factory from the JNDI provider? Exception in thread "main" java.lang.ClassCastException: javax.naming.Reference cannot be cast to javax.jms.ConnectionFactory Here is an abbreviated version of the JMS client that includes only its start() and stop() methods. The exception occurs on the first line in method start() which attempts to retrieve the connection factory from the JNDI provider, a remote LDAP server. The JMS connection factory and destination objects are on a remote JMS server. class JmsClient { private ConnectionFactory connectionFactory; private Connection connection; private Session session; private MessageConsumer consumer; private Topic topic; public void stop() throws JMSException { consumer.close(); session.close(); connection.close(); } public void start(Context context, String connectionFactoryName, String topicName) throws NamingException, JMSException { // ClassCastException occurs when retrieving connection factory. connectionFactory = (ConnectionFactory) context.lookup(connectionFactoryName); connection = connectionFactory.createConnection("username","password"); session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); topic = (Topic) context.lookup(topicName); consumer = session.createConsumer(topic); connection.start(); } private static Context getInitialContext() throws NamingException, IOException { String filename = "context.properties"; Properties props = new Properties(); props.load(new FileInputStream(filename)); return new InitialContext(props); } }

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  • Determining whether geographic point is within X meters of a state border (using shapefile for borde

    - by DanM
    So I'm writing a Java app, and I've got an ESRI Shapefile which contains the borders of all the U.S. states. What I need is to be able to determine whether any given lat/lon point is within a specified distance from ANY state border line - i.e., I will not be specifying a particular border line, just need to see whether the point is close to any of them. The solution does NOT have to be very precise at all; e.g. I don't need to be dealing with measuring perpendicular to the border, or whatever. Just checking to see if going X meters north, south, east or west would result in crossing a border would be more than sufficient. The solution DOES have to be computationally efficient, as I'll be performing a huge number of these calculations. I'm planning to use the GeoTools library (though if there's a simpler option, I'm all for it) with the Shapefile plugin. What I don't really understand is: Once I've got the shapefile loaded into memory, how do I check to see whether I'm near a border? Thanks! -Dan

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  • Basic example of placing two component on one JPanel container?

    - by Bernard
    Here is my code to add to component (JTextArea and JList) to a panel and put it on the frame. Can I divide half/half by BorderLayout? If yes why mine looks messy one stays up one down? What is the other alternative? Regards, Bernard import java.awt.*; import javax.swing.BorderFactory; import javax.swing.border.Border; import javax.swing.JList; import javax.swing.JScrollPane; import javax.swing.JPanel; import javax.swing.JFrame; import javax.swing.JTextArea; public class SimpleBorder { public static void main(String[] args) { JFrame frame = new JFrame(); frame.setSize(500,500); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Border etched = (Border) BorderFactory.createEtchedBorder(); String[] items = {"A", "B", "C", "D"}; JList list = new JList(items); JTextArea text = new JTextArea(10, 40); JScrollPane scrol = new JScrollPane(text); JScrollPane scrol2 = new JScrollPane(list); JPanel panel= new JPanel(); panel.add(scrol2,BorderLayout.WEST); panel.add(scrol, BorderLayout.EAST); panel.setBorder(etched); frame.add(panel); frame.setVisible(true); } }

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  • JLabel not greyed out when disabled, when HTML text displayed

    - by bguiz
    How do I get a JLabel displaying a HTML string to appear greyed out (which is the behaviour of JLabels that don't display HTML text)? Is there another way than actually changing the colour myself by modifying the foreground property? JLabel label1 = new JLabel("Normal text"); JLabel label2 = new JLabel("<html>HTML <b>text</b>"); // Both labels are now black in colour label1.setEnabled(false); label2.setEnabled(false); // label1 is greyed out, label2 is still black in colour Thank you very much for all of your responses. From what I gather, it seems that Java doesn't support automatic greying out of JLabels when they use HTML text. Suraj's solution has come closest to the fix considering the limitations. I have however, tried a different out-of-the box approach, where I have put the HTML text JLabels inside of an inner JPanel and did this: mInnerPanel.setEnabled(shouldShow); //shouldShow is a boolean value Which hasn't worked. Any suggestions for this way? EDIT: Added implemented solution.

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  • Eclipse does not refresh project files in package explorer view

    - by EugeneP
    Today I see a strange behaviour of Eclipse 3.5.2 for the first time in 3 months. First, when I run a main function, it runs a previously compiled version. Let's say I press Ctrl+F11 in the window with an open java class and existing main function. Usually it rebuilds the class and runs a new version. Today even if there was a compile mistake, it would run fine. So I guess it does not recompile the class. Next, more strangely, if I intentionally make a mistake in the code and Eclipse underlines those lines in red, still the project Explorer does not mark them as containing errors. They remain of grey color if there were not any errors. First I did not know how to solve this problem. I tried to reopen the project, restart Eclipse and finally reboot the OS. After the tenth attempt, after rebooting, Eclipse said that all project's files are "OUT OF SYNC with the file system". When I pressed "Refresh" - F5 on a project's header name in Project Explorer it finally marked all the files with errors as containing errors and running the main function gave the desired result. An hour of my work passed and this happened again , with the other project. All the same. No marking of files as red, running no matter what old version of class with no compile errors. And since Eclipse does not tell that files are out of sync, simply pressing F5 on a project cannot help. What can you suggest?

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  • Terminal / Panel PC - Single Server Solution: Client/Server or RDP?

    - by StillLearning
    Hi, Our current setup involves a touch screen panel pc with embedded windows, that is connected via network to a server / dedicated pc, within the same physical location. Each of our 'units' has this hardware setup. For a quick resolution we deploy our application to the dedicated pc, and have the panel pc remote desktop to an account which then activates the application. This works but seems a little clunky / rough approach. We did this because the panel pc is rather limited. Now that we have more time, I was wondering if I should separate the application into a gui / application. Deploy the gui logic on the panel pc, and the business/database logic on the dedicated pc. The app is in Java so I was wondering what technology would be best? I was thinking of using RMI, but its not really a client/server app, as there is only one client. Should I stick with RMI, or use Sockets or something else? It will be easy to implement as the application is old, and manually wraps and unwraps data which passes through one class / method call to remote services. All I would have to do is 'RMI' this one method call, and the app will do its own stuff. Cheers.

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  • Need a design pattern for representing multiple information sources

    - by hsmit
    I'm building a Java application that retrieves information from differing information sources. I'm using a sensor, a set of RecordStores and a few online web services. In the basic application all these resources are loaded by default. Some of these sources are directly read in a separate thread (load database, read sensor etc.). From this basic application some functions are started that use these sources. The classes that contain these functions (usually combining multiple sources information) are currently paramterized with a set of resources like this: AppPart a1 = new AppPart(source1, source2, source3); I could also do it like this AppPart a1 = new AppPart(this); ..where I need to make my sources public in order to read them. I'm also thinking about a kind of stage/collection to publish all sources on, e.g: public SourceCollectionStage sStage = new SourceCollectionStage(); and later: sStage.getSensor(); .. for example. What do you guys think is the best or most often used way to do this? Btw: the user interface is often implemented by the specific funtion classes, not by the main class. Should I do this in another way?

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