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  • To save to log out time

    - by user311078
    I want to save log out time when user close the Browser without clicking log out button using asp.net with C# and SQL server 2005. kindly let me know the way as well as code.. Thanks in advance

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  • How do you make a character jump, both on objects and just normal jump?

    - by haxerflaxer
    Hi, I'm kind of a beginner when it comes to java programming, and I have a project in school where I'm going to create a game much like Icy Tower. And my question is, how am I going to write to make the character stand on the ground and be able to jump up on objects? Here's my code so far: Part one package Sprites; import java.awt.Image; import java.awt.event.KeyEvent; import javax.swing.ImageIcon; public class jumper { private String jump = "oka.png"; private int dx; private int dy; private int x; private int y; private Image image; public jumper() { ImageIcon ii = new ImageIcon(this.getClass().getResource(jump)); image = ii.getImage(); x = 50; y = 100; } public void move() { x += dx; y += dy; } public int getX() { return x; } public int getY() { return y; } public Image getImage() { return image; } public void keyPressed(KeyEvent e) { int key = e.getKeyCode(); if (key == KeyEvent.VK_LEFT) { dx = -5; ImageIcon ii = new ImageIcon(this.getClass().getResource("oki.png")); image = ii.getImage(); } if (key == KeyEvent.VK_RIGHT){ dx = 5; ImageIcon ii = new ImageIcon(this.getClass().getResource("oka.png")); image = ii.getImage(); } if (key == KeyEvent.VK_SPACE) { dy = -5; } if (key == KeyEvent.VK_DOWN) { dy = 5; } } public void keyReleased(KeyEvent e) { int key = e.getKeyCode(); if (key == KeyEvent.VK_LEFT) { dx = 0; } if (key == KeyEvent.VK_RIGHT){ dx = 0; } if (key == KeyEvent.VK_SPACE) { dy = 0; } if (key == KeyEvent.VK_DOWN) { dy = 0; } } } Part two package Sprites; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyAdapter; import java.awt.event.KeyEvent; import javax.swing.JPanel; import javax.swing.Timer; public class board extends JPanel implements ActionListener { private Timer klocka; private jumper jumper; public board() { addKeyListener(new TAdapter()); setFocusable(true); setBackground(Color.WHITE); setDoubleBuffered(true); jumper = new jumper(); klocka = new Timer(5, this); klocka.start(); } public void paint(Graphics g) { super.paint(g); Graphics2D g2d = (Graphics2D)g; g2d.drawImage(jumper.getImage(), jumper.getX(), jumper.getY(), this); Toolkit.getDefaultToolkit().sync(); g.dispose(); } public void actionPerformed(ActionEvent e) { jumper.move(); repaint(); } private class TAdapter extends KeyAdapter { public void keyReleased(KeyEvent e) { jumper.keyReleased(e); } public void keyPressed(KeyEvent e) { jumper.keyPressed(e); } } } Part three package Sprites; import javax.swing.JFrame; public class RType extends JFrame { public RType() { add(new board()); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setSize(800, 600); setLocationRelativeTo(null); setTitle("R - type"); setResizable(false); setVisible(true); } public static void main(String[] args) { new RType(); } } I really appreciate all the help I can get!

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  • How to make a character jump, both on objects and just normal jump.

    - by haxerflaxer
    Hi, I'm kind of a beginner when it comes to java programming, and I have a project in school where I'm going to create a game much like Icy Tower. And my question is, how am I going to write to make the character stand on the ground and be able to jump up on objects? Here's my code so far: Part one package Sprites; import java.awt.Image; import java.awt.event.KeyEvent; import javax.swing.ImageIcon; public class jumper { private String jump = "oka.png"; private int dx; private int dy; private int x; private int y; private Image image; public jumper() { ImageIcon ii = new ImageIcon(this.getClass().getResource(jump)); image = ii.getImage(); x = 50; y = 100; } public void move() { x += dx; y += dy; } public int getX() { return x; } public int getY() { return y; } public Image getImage() { return image; } public void keyPressed(KeyEvent e) { int key = e.getKeyCode(); if (key == KeyEvent.VK_LEFT) { dx = -5; ImageIcon ii = new ImageIcon(this.getClass().getResource("oki.png")); image = ii.getImage(); } if (key == KeyEvent.VK_RIGHT){ dx = 5; ImageIcon ii = new ImageIcon(this.getClass().getResource("oka.png")); image = ii.getImage(); } if (key == KeyEvent.VK_SPACE) { dy = -5; } if (key == KeyEvent.VK_DOWN) { dy = 5; } } public void keyReleased(KeyEvent e) { int key = e.getKeyCode(); if (key == KeyEvent.VK_LEFT) { dx = 0; } if (key == KeyEvent.VK_RIGHT){ dx = 0; } if (key == KeyEvent.VK_SPACE) { dy = 0; } if (key == KeyEvent.VK_DOWN) { dy = 0; } } } Part two package Sprites; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyAdapter; import java.awt.event.KeyEvent; import javax.swing.JPanel; import javax.swing.Timer; public class board extends JPanel implements ActionListener { private Timer klocka; private jumper jumper; public board() { addKeyListener(new TAdapter()); setFocusable(true); setBackground(Color.WHITE); setDoubleBuffered(true); jumper = new jumper(); klocka = new Timer(5, this); klocka.start(); } public void paint(Graphics g) { super.paint(g); Graphics2D g2d = (Graphics2D)g; g2d.drawImage(jumper.getImage(), jumper.getX(), jumper.getY(), this); Toolkit.getDefaultToolkit().sync(); g.dispose(); } public void actionPerformed(ActionEvent e) { jumper.move(); repaint(); } private class TAdapter extends KeyAdapter { public void keyReleased(KeyEvent e) { jumper.keyReleased(e); } public void keyPressed(KeyEvent e) { jumper.keyPressed(e); } } } Part three package Sprites; import javax.swing.JFrame; public class RType extends JFrame { public RType() { add(new board()); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setSize(800, 600); setLocationRelativeTo(null); setTitle("R - type"); setResizable(false); setVisible(true); } public static void main(String[] args) { new RType(); } } I really appreciate all the help I can get!

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  • appengine log console extremely slow

    - by Joey
    I am using the python app engine and finding that the log console on the local development server is terribly slow. Output to this window seems to show in chunks of about 5-15 lines every second. Is that typical? I find that it's so slow that it hinders my debugging time waiting for log data to appear.

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  • How to enable Apache internal debug log (Win32)

    - by Michael
    On Win32 I'm getting intermittent output like this at page header: order allow,deny deny from allorder allow,deny deny from all I'm running php script which has number of .htaccess files in each subfolder. I need to understand why sometimes apache is just dumping me a content of this files. So just wondering if there is any way to enable debug log. I've tried ErrorLog "e:/wamp/logs/apache_error.log" LogLevel debug However can't see any debug output neither in error nor in access logs. Thanks

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  • Trying to understand crash log output

    - by John Smith
    I'm trying to understand debug output from a crash log. I have the following line from the crashlog: 22 FG 0x00022b94 0x1000 + 138132 I understand how to use atos on 0x00022b94 to get the source code location. What I would like to know is why the crash log helpfully splits that number into 0x1000 + 138132? I have googled and the googles failed me.

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  • Saving data from another model (my own log system)

    - by user331321
    Hi! I´m trying to write a log system for my CakePHP intranet. What i need is to store de username/datetime whene someone tryes to login. My login code is on the clients_controller and i need to store the data on a model called log (i have the model, controller, view... but they are not related) how can i achive that? thank you

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  • java.sql.SQLException: ORA-06502: PL/SQL: numeric or value error: character string buffer too small

    - by jack
    Hi I got an email from a user when he sees the following error output when he's using our web site. java.sql.SQLException: ORA-06502: PL/SQL: numeric or value error: character string buffer too small ORA-06512: at "WEB_OWNER.SSFP_GET_WE_OBJ", line 300 ORA-06512: at line 1 at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:137) at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:315) at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:281) This is error from oracle webconnect, Oracle Application Server Containers for J2EE 10g (10.1.2.3.0). Any idea?

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  • Java Class path problem in cent os..

    - by Ramesh
    I have installed java in centos5 classpath is not working .... my bash_profile export PATH=$PATH:/zzz/jdk1.6.0_03/bin/ export JAVA_HOME=/zzz/jdk1.6.0_03/bin/java/ export CLASSPATH=$CLASSPATH:/zzz/aa/mysql.jar:. java -version java version "1.6.0" OpenJDK Runtime Environment (build 1.6.0-b09) OpenJDK Server VM (build 1.6.0-b09, mixed mode)

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  • Problems with calendar application on Android 2.1

    - by Rick
    Hi, I have compiled the android 2.1 source code and I can start the emulator. But I can't launch calendar application. Every time I tried to lauch the calendar application, it crashed. The log is as following: // CRASH: com.android.calendar (pid 272) // Short Msg: java.lang.NullPointerException // Long Msg: java.lang.NullPointerException // Build Label: android:generic/generic/generic/:2.1-update1/ERE27/eng.root.20100317.113135:eng/test-keys // Build Changelist: -1 // Build Time: 1268798948 // ID: // Tag: AndroidRuntime // java.lang.NullPointerException: // at com.android.providers.calendar.CalendarSyncAdapter.onAccountsChanged(CalendarSyncAdapter.java:1400) // at android.content.AbstractSyncableContentProvider$1.onAccountsUpdated(AbstractSyncableContentProvider.java:189) // at android.accounts.AccountManager$10.run(AccountManager.java:826) // at android.os.Handler.handleCallback(Handler.java:587) // at android.os.Handler.dispatchMessage(Handler.java:92) // at android.os.Looper.loop(Looper.java:123) // at android.app.ActivityThread.main(ActivityThread.java:4363) // at java.lang.reflect.Method.invokeNative(Method.java:-2) // at java.lang.reflect.Method.invoke(Method.java:521) // at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) // at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) // at dalvik.system.NativeStart.main(NativeStart.java:-2) has anyone met this problem, or any suggestions on how to fix it? Thanks very much!! Rick

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  • htmlunit eofexception

    - by ihtram
    hi, i am using htmlunit to parse a page. but when i tried to get page from url i got an exception, lets have a look on my code: WebClient wc = new WebClient(BrowserVersion.FIREFOX_3); HtmlPage page = wc.getPage(strUrl); when compilet goes to wc.getPage(strUrl) it throws an exception i.e. java.io.EOFException at java.util.zip.GZIPInputStream.readUByte(Unknown Source) at java.util.zip.GZIPInputStream.readUShort(Unknown Source) at java.util.zip.GZIPInputStream.readHeader(Unknown Source) at java.util.zip.GZIPInputStream.(Unknown Source) at java.util.zip.GZIPInputStream.(Unknown Source) at com.gargoylesoftware.htmlunit.WebResponseData.getBody(WebResponseData.java:129) at com.gargoylesoftware.htmlunit.WebResponseData.(WebResponseData.java:87) at com.gargoylesoftware.htmlunit.HttpWebConnection.newWebResponseDataInstance(HttpWebConnection.java:452) at com.gargoylesoftware.htmlunit.HttpWebConnection.makeWebResponse(HttpWebConnection.java:432) at com.gargoylesoftware.htmlunit.HttpWebConnection.getResponse(HttpWebConnection.java:104) at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseFromWebConnection(WebClient.java:1407) at com.gargoylesoftware.htmlunit.WebClient.loadWebResponse(WebClient.java:1340) at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:299) at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:360) at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:345) at com.htmlunit.test.IHGHotelTest.main(IHGHotelTest.java:39) any one have an idea about it

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  • Why do I get a null pointer exception from TabWidget?

    - by rushinge
    I'm writing an android program in which I have an activity that uses tabs. The Activity public class UnitActivity extends TabActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); TabHost tabHost = getTabHost(); TabSpec spec; Resources res = getResources(); LayoutInflater.from(this).inflate(R.layout.unit_view, tabHost.getTabContentView(), true); spec = tabHost.newTabSpec("controls"); spec.setIndicator("Control", res.getDrawable(R.drawable.ic_tab_equalizer)); spec.setContent(R.id.txtview); tabHost.addTab(spec); } } The XML referenced by R.layout.unit_view <?xml version="1.0" encoding="utf-8"?> <TabHost xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/tabhost" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dp"> <TabWidget android:id="@android:id/tabs" android:layout_width="fill_parent" android:layout_height="wrap_content"/> <FrameLayout android:id="@android:id/tabcontent" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dp"> <TextView android:id="@+id/txtview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="bottom" android:text="nullpointer this!" /> </FrameLayout> </LinearLayout> </TabHost> As far as I can see I'm doing the same thing I see in the tabs1 api sample from the android sdk. I've tried "getLayoutInflator()" instead of "LayoutInflator.from(this)" with the same result. If I replace the LayoutInflater line with "setContentView(R.layout.unit_view)" my program doesn't crash with a null pointer exception but my content is completely blank and empty. I get the tab and that's it. I've checked to make sure R.layout.unit_view and tabHost are not null when it runs the LayoutInflater line and they seem to be fine. They're defenitely not null. I've also checked to make sure LayoutInflater.from(this) returns a valid layout inflater object and it does. The logcat indicating the error says E/AndroidRuntime( 541): java.lang.NullPointerException E/AndroidRuntime( 541): at android.widget.TabWidget.dispatchDraw(TabWidget.java:206) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.View.draw(View.java:6538) E/AndroidRuntime( 541): at android.widget.FrameLayout.draw(FrameLayout.java:352) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1531) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.View.draw(View.java:6538) E/AndroidRuntime( 541): at android.widget.FrameLayout.draw(FrameLayout.java:352) E/AndroidRuntime( 541): at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1830) E/AndroidRuntime( 541): at android.view.ViewRoot.draw(ViewRoot.java:1349) E/AndroidRuntime( 541): at android.view.ViewRoot.performTraversals(ViewRoot.java:1114) E/AndroidRuntime( 541): at android.view.ViewRoot.handleMessage(ViewRoot.java:1633) E/AndroidRuntime( 541): at android.os.Handler.dispatchMessage(Handler.java:99) E/AndroidRuntime( 541): at android.os.Looper.loop(Looper.java:123) E/AndroidRuntime( 541): at android.app.ActivityThread.main(ActivityThread.java:4363) E/AndroidRuntime( 541): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime( 541): at java.lang.reflect.Method.invoke(Method.java:521) E/AndroidRuntime( 541): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) E/AndroidRuntime( 541): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) E/AndroidRuntime( 541): at dalvik.system.NativeStart.main(Native Method) I/Process ( 61): Sending signal. PID: 541 SIG: 3 I/dalvikvm( 541): threadid=7: reacting to signal 3 I/dalvikvm( 541): Wrote stack trace to '/data/anr/traces.txt' Anybody have any idea how I can get this content into a tab without crashing my application? My actual program is more complex and has more than one tab but I simplified it down to this in an attempt to find out why it's crashing but it still crashes and I don't know why. If I don't use LayoutInflator my program doesn't crash but I don't get any content either, just tabs.

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  • All libGDX input statements are returning TRUE at once

    - by MowDownJoe
    I'm fooling around with Box2D and libGDX and running into a peculiar problem with polling for input. Here's the code for the Screen's render() loop: @Override public void render(float delta) { Gdx.gl20.glClearColor(0, 0, .2f, 1); Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT); camera.update(); game.batch.setProjectionMatrix(camera.combined); debugRenderer.render(world, camera.combined); if(Gdx.input.isButtonPressed(Keys.LEFT)){ Gdx.app.log("Input", "Left is being pressed."); pushyThingyBody.applyForceToCenter(-10f, 0); } if(Gdx.input.isButtonPressed(Keys.RIGHT)){ Gdx.app.log("Input", "Right is being pressed."); pushyThingyBody.applyForceToCenter(10f, 0); } world.step((1f/45f), 6, 2); } And the constructor is largely just setting up the World, Box2DDebugRenderer, and all the Bodies in the world: public SandBox(PhysicsSandboxGame game) { this.game = game; camera = new OrthographicCamera(800, 480); camera.setToOrtho(false); world = new World(new Vector2(0, -9.8f), true); debugRenderer = new Box2DDebugRenderer(); BodyDef bodyDef = new BodyDef(); bodyDef.type = BodyType.DynamicBody; bodyDef.position.set(100, 300); body = world.createBody(bodyDef); CircleShape circle = new CircleShape(); circle.setRadius(6f); FixtureDef fixtureDef = new FixtureDef(); fixtureDef.shape = circle; fixtureDef.density = .5f; fixtureDef.friction = .4f; fixtureDef.restitution = .6f; fixture = body.createFixture(fixtureDef); circle.dispose(); BodyDef groundBodyDef = new BodyDef(); groundBodyDef.position.set(new Vector2(0, 10)); groundBody = world.createBody(groundBodyDef); PolygonShape groundBox = new PolygonShape(); groundBox.setAsBox(camera.viewportWidth, 10f); groundBody.createFixture(groundBox, 0f); groundBox.dispose(); BodyDef pushyThingyBodyDef = new BodyDef(); pushyThingyBodyDef.type = BodyType.DynamicBody; pushyThingyBodyDef.position.set(new Vector2(400, 30)); pushyThingyBody = world.createBody(pushyThingyBodyDef); PolygonShape pushyThingyShape = new PolygonShape(); pushyThingyShape.setAsBox(40f, 10f); FixtureDef pushyThingyFixtureDef = new FixtureDef(); pushyThingyFixtureDef.shape = pushyThingyShape; pushyThingyFixtureDef.density = .4f; pushyThingyFixtureDef.friction = .1f; pushyThingyFixtureDef.restitution = .5f; pushyFixture = pushyThingyBody.createFixture(pushyThingyFixtureDef); pushyThingyShape.dispose(); } Testing this on the desktop. Basically, whenever I hit the appropriate keys, neither of the if statements in the loop return true. However, when I click in the window, both statements return true, resulting in a 0 net force on the body. Why is this?

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  • OutOfMemoryError trying to upload to Blobstore locally

    - by jeanh
    Hi all, I am trying to set up a basic file upload to blobstore, but I get this OutOfMemoryError: WARNING: Error for /_ah/upload/ aghvbWdkcmVzc3IcCxIVX19CbG9iVXBsb2FkU2Vzc2lvbl9fGMACDA java.lang.OutOfMemoryError: Java heap space at java.util.Arrays.copyOf(Arrays.java:2786) at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:71) at javax.mail.internet.MimeMultipart.readTillFirstBoundary(MimeMultipart.java: 316) at javax.mail.internet.MimeMultipart.parse(MimeMultipart.java:186) at javax.mail.internet.MimeMultipart.getCount(MimeMultipart.java:109) at com.google.appengine.api.blobstore.dev.UploadBlobServlet.handleUpload(UploadBlobServlet.java: 135) at com.google.appengine.api.blobstore.dev.UploadBlobServlet.access $000(UploadBlobServlet.java:72) at com.google.appengine.api.blobstore.dev.UploadBlobServlet $1.run(UploadBlobServlet.java:100) at java.security.AccessController.doPrivileged(Native Method) at com.google.appengine.api.blobstore.dev.UploadBlobServlet.doPost(UploadBlobServlet.java: 98) at javax.servlet.http.HttpServlet.service(HttpServlet.java:713) at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java: 511); I used the Memory Analyzer on Eclipse and it said that the memory leak suspect is QueuedThreadPool. I found this information about a memory leak bug: http://jira.codehaus.org/browse/JETTY-1188 Has anyone else had this issue? Thanks, Jean

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  • What are the disadvantages of self-encapsulation?

    - by Dave Jarvis
    Background Tony Hoare's billion dollar mistake was the invention of null. Subsequently, a lot of code has become riddled with null pointer exceptions (segfaults) when software developers try to use (dereference) uninitialized variables. In 1989, Wirfs-Brock and Wikerson wrote: Direct references to variables severely limit the ability of programmers to re?ne existing classes. The programming conventions described here structure the use of variables to promote reusable designs. We encourage users of all object-oriented languages to follow these conventions. Additionally, we strongly urge designers of object-oriented languages to consider the effects of unrestricted variable references on reusability. Problem A lot of software, especially in Java, but likely in C# and C++, often uses the following pattern: public class SomeClass { private String someAttribute; public SomeClass() { this.someAttribute = "Some Value"; } public void someMethod() { if( this.someAttribute.equals( "Some Value" ) ) { // do something... } } public void setAttribute( String s ) { this.someAttribute = s; } public String getAttribute() { return this.someAttribute; } } Sometimes a band-aid solution is used by checking for null throughout the code base: public void someMethod() { assert this.someAttribute != null; if( this.someAttribute.equals( "Some Value" ) ) { // do something... } } public void anotherMethod() { assert this.someAttribute != null; if( this.someAttribute.equals( "Some Default Value" ) ) { // do something... } } The band-aid does not always avoid the null pointer problem: a race condition exists. The race condition is mitigated using: public void anotherMethod() { String someAttribute = this.someAttribute; assert someAttribute != null; if( someAttribute.equals( "Some Default Value" ) ) { // do something... } } Yet that requires two statements (assignment to local copy and check for null) every time a class-scoped variable is used to ensure it is valid. Self-Encapsulation Ken Auer's Reusability Through Self-Encapsulation (Pattern Languages of Program Design, Addison Wesley, New York, pp. 505-516, 1994) advocated self-encapsulation combined with lazy initialization. The result, in Java, would resemble: public class SomeClass { private String someAttribute; public SomeClass() { setAttribute( "Some Value" ); } public void someMethod() { if( getAttribute().equals( "Some Value" ) ) { // do something... } } public void setAttribute( String s ) { this.someAttribute = s; } public String getAttribute() { String someAttribute = this.someAttribute; if( someAttribute == null ) { setAttribute( createDefaultValue() ); } return someAttribute; } protected String createDefaultValue() { return "Some Default Value"; } } All duplicate checks for null are superfluous: getAttribute() ensures the value is never null at a single location within the containing class. Efficiency arguments should be fairly moot -- modern compilers and virtual machines can inline the code when possible. As long as variables are never referenced directly, this also allows for proper application of the Open-Closed Principle. Question What are the disadvantages of self-encapsulation, if any? (Ideally, I would like to see references to studies that contrast the robustness of similarly complex systems that use and don't use self-encapsulation, as this strikes me as a fairly straightforward testable hypothesis.)

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  • Cannot understand NullPointerException with custom adapter

    - by ganesh
    hi, I am trying to create a list view which as TextView that can display html content , an WebView and other basic TextViews.I tried to extend SimpleAdapter but i struck with the problem ,I will be glad if someone can point out the mistake i am doing. In onCreate method ArrayList mylist= resultfromXmlparser(); adap = new MyAdapter(TourLandingPage.this, mylist, R.layout.row, new String[] {"Name", "desc","Duration","Price","imgurl"}, new int[] {R.id.productname,R.id.des,R.id.duration,R.id.pricefrom,R.id.photo}); setListAdapter(adap); My custom Adapter looks like this private class MyAdapter extends SimpleAdapter { ArrayList<HashMap<String,String>> elements; Context ctx; public MyAdapter(Context context, ArrayList<HashMap<String,String>> mylist,int textViewResourceId,String[] names,int[] resouceid) { super(context, mylist,textViewResourceId, names,resouceid); this.elements=mylist; this.ctx=context; } @Override public int getCount() { return elements.size(); } @Override public Object getItem(int position) { return elements.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { RelativeLayout rowLayout; if (convertView == null) { rowLayout = (RelativeLayout) LayoutInflater.from(ctx).inflate(R.layout.rowfor_tourlist, parent, false); } else { rowLayout = (RelativeLayout) convertView; } TextView in = (TextView)rowLayout.findViewById(R.id.introduction); TextView du = (TextView)rowLayout.findViewById(R.id.duration); TextView pf = (TextView)rowLayout.findViewById(R.id.pricefrom); TextView pn = (TextView)rowLayout.findViewById(R.id.productname); WebView wv=(WebView)rowLayout.findViewById(R.id.photo); in.setText(Html.fromHtml(mylist.get(position).get("desc"))); du.setText(mylist.get(position).get("Duration")); pf.setText(mylist.get(position).get("Price")); pn.setText(mylist.get(position).get("Name")); wv.getSettings().setJavaScriptEnabled(true); wv.loadUrl(mylist.get(position).get("imgurl")); return convertView; } }//class and my row.xml file looks like RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" TextView android:id="@+id/productname" ...... LinearLayout android:layout_width="wrap_content" android:layout_height="60dip" android:layout_margin="5dip" android:layout_below="@id/productname" android:orientation="horizontal" android:id="@+id/lay1" WebView android:id="@+id/photo" .... TextView android:id="@+id/introduction" ...... LinearLayout TextView android:id="@+id/duration" .... TextView android:id="@+id/pricefrom" ..... RelativeLayout The error i was getting was 04-28 19:46:17.749: ERROR/AndroidRuntime(976): Uncaught handler: thread main exiting due to uncaught exception 04-28 19:46:17.769: ERROR/AndroidRuntime(976): java.lang.NullPointerException 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.ListView.setupChild(ListView.java:1693) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.ListView.makeAndAddView(ListView.java:1671) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.ListView.fillDown(ListView.java:637) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.ListView.fillFromTop(ListView.java:694) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.ListView.layoutChildren(ListView.java:1521) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.AbsListView.onLayout(AbsListView.java:1113) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.View.layout(View.java:6831) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1108) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.onLayout(LinearLayout.java:920) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.View.layout(View.java:6831) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.onLayout(LinearLayout.java:918) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.View.layout(View.java:6831) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.View.layout(View.java:6831) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.LinearLayout.onLayout(LinearLayout.java:918) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.View.layout(View.java:6831) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.View.layout(View.java:6831) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.ViewRoot.performTraversals(ViewRoot.java:996) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.view.ViewRoot.handleMessage(ViewRoot.java:1633) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.os.Handler.dispatchMessage(Handler.java:99) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.os.Looper.loop(Looper.java:123) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at android.app.ActivityThread.main(ActivityThread.java:4338) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at java.lang.reflect.Method.invokeNative(Native Method) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at java.lang.reflect.Method.invoke(Method.java:521) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 04-28 19:46:17.769: ERROR/AndroidRuntime(976): at dalvik.system.NativeStart.main(Native Method) 04-28 19:46:17.789: INFO/Process(52): Sending signal. PID: 976 SIG: 3 04-28 19:46:17.799: INFO/dalvikvm(976): threadid=7: reacting to signal 3 04-28 19:46:17.829: INFO/dalvikvm(976): Wrote stack trace to '/data/anr/traces.txt'

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  • Rotation of viewplatform in Java3D

    - by user29163
    I have just started with Java3D programming. I thought I had built up some basic intuition about how the scene graph works, but something that should work, does not work. I made a simple program for rotating a pyramid around the y-axis. This was done just by adding a RotationInterpolator R to the TransformGroup above the pyramid. Then I thought hey, can I now remove the RotationInterpolator from this TransformGroup, then add it to the TransformGroup above my ViewPlatform leaf. This should work if I have understood how things work. Adding the RotationInterpolator to this TransformGroup, should make the children of this TransformGroup rotate, and the ViewingPlatform is a child of the TransformGroup. Any ideas on where my reasoning is flawed? Here is the code for setting up the universe, and the view branchgroup. import java.awt.*; import java.awt.event.*; import javax.media.j3d.*; import javax.vecmath.*; public class UniverseBuilder { // User-specified canvas Canvas3D canvas; // Scene graph elements to which the user may want access VirtualUniverse universe; Locale locale; TransformGroup vpTrans; View view; public UniverseBuilder(Canvas3D c) { this.canvas = c; // Establish a virtual universe that has a single // hi-res Locale universe = new VirtualUniverse(); locale = new Locale(universe); // Create a PhysicalBody and PhysicalEnvironment object PhysicalBody body = new PhysicalBody(); PhysicalEnvironment environment = new PhysicalEnvironment(); // Create a View and attach the Canvas3D and the physical // body and environment to the view. view = new View(); view.addCanvas3D(c); view.setPhysicalBody(body); view.setPhysicalEnvironment(environment); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); // Create a ViewPlatform object, and its associated // TransformGroup object, and attach it to the root of the // subgraph. Attach the view to the view platform. Transform3D t = new Transform3D(); Transform3D s = new Transform3D(); t.set(new Vector3f(0.0f, 0.0f, 10.0f)); t.rotX(-Math.PI/4); s.set(new Vector3f(0.0f, 0.0f, 10.0f)); //forandre verdier her for å endre viewing position t.mul(s); ViewPlatform vp = new ViewPlatform(); vpTrans = new TransformGroup(t); vpTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); // Rotator stuff Transform3D yAxis = new Transform3D(); //yAxis.rotY(Math.PI/2); Alpha rotationAlpha = new Alpha( -1, Alpha.INCREASING_ENABLE, 0, 0,4000, 0, 0, 0, 0, 0); RotationInterpolator rotator = new RotationInterpolator( rotationAlpha, vpTrans, yAxis, 0.0f, (float) Math.PI*2.0f); RotationInterpolator rotator2 = new RotationInterpolator( rotationAlpha, vpTrans); BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 1000.0); rotator.setSchedulingBounds(bounds); vpTrans.addChild(rotator); vpTrans.addChild(vp); vpRoot.addChild(vpTrans); view.attachViewPlatform(vp); // Attach the branch graph to the universe, via the // Locale. The scene graph is now live! locale.addBranchGraph(vpRoot); } public void addBranchGraph(BranchGroup bg) { locale.addBranchGraph(bg); } }

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  • Trouble rotating viewplatform in Java3D [closed]

    - by user29163
    I have just started with Java3D programming. I thought I had built up some basic intuition about how the scene graph works, but something that should work, does not work. I made a simple program for rotating a pyramid around the y-axis. This was done just by adding a RotationInterpolator R to the TransformGroup above the pyramid. Then I thought hey, can I now remove the RotationInterpolator from this TransformGroup, then add it to the TransformGroup above my ViewPlatform leaf. This should work if I have understood how things work. Adding the RotationInterpolator to this TransformGroup, should make the children of this TransformGroup rotate, and the ViewingPlatform is a child of the TransformGroup. Any ideas on where my reasoning is flawed? Here is the code for setting up the universe, and the view branchgroup. import java.awt.*; import java.awt.event.*; import javax.media.j3d.*; import javax.vecmath.*; public class UniverseBuilder { // User-specified canvas Canvas3D canvas; // Scene graph elements to which the user may want access VirtualUniverse universe; Locale locale; TransformGroup vpTrans; View view; public UniverseBuilder(Canvas3D c) { this.canvas = c; // Establish a virtual universe that has a single // hi-res Locale universe = new VirtualUniverse(); locale = new Locale(universe); // Create a PhysicalBody and PhysicalEnvironment object PhysicalBody body = new PhysicalBody(); PhysicalEnvironment environment = new PhysicalEnvironment(); // Create a View and attach the Canvas3D and the physical // body and environment to the view. view = new View(); view.addCanvas3D(c); view.setPhysicalBody(body); view.setPhysicalEnvironment(environment); // Create a BranchGroup node for the view platform BranchGroup vpRoot = new BranchGroup(); // Create a ViewPlatform object, and its associated // TransformGroup object, and attach it to the root of the // subgraph. Attach the view to the view platform. Transform3D t = new Transform3D(); Transform3D s = new Transform3D(); t.set(new Vector3f(0.0f, 0.0f, 10.0f)); t.rotX(-Math.PI/4); s.set(new Vector3f(0.0f, 0.0f, 10.0f)); //forandre verdier her for å endre viewing position t.mul(s); ViewPlatform vp = new ViewPlatform(); vpTrans = new TransformGroup(t); vpTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE); // Rotator stuff Transform3D yAxis = new Transform3D(); //yAxis.rotY(Math.PI/2); Alpha rotationAlpha = new Alpha( -1, Alpha.INCREASING_ENABLE, 0, 0,4000, 0, 0, 0, 0, 0); RotationInterpolator rotator = new RotationInterpolator( rotationAlpha, vpTrans, yAxis, 0.0f, (float) Math.PI*2.0f); RotationInterpolator rotator2 = new RotationInterpolator( rotationAlpha, vpTrans); BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 1000.0); rotator.setSchedulingBounds(bounds); vpTrans.addChild(rotator); vpTrans.addChild(vp); vpRoot.addChild(vpTrans); view.attachViewPlatform(vp); // Attach the branch graph to the universe, via the // Locale. The scene graph is now live! locale.addBranchGraph(vpRoot); } public void addBranchGraph(BranchGroup bg) { locale.addBranchGraph(bg); } }

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  • JNI String Corruption

    - by Chris Dennett
    Hi everyone, I'm getting weird string corruption across JNI calls which is causing problems on the the Java side. Every so often, I'll get a corrupted string in the passed array, which sometimes has existing parts of the original non-corrupted string. The C++ code is supposed to set the first index of the array to the address, it's a nasty hack to get around method call limitations. Additionally, the application is multi-threaded. remoteaddress[0]: 10.1.1.2:49153 remoteaddress[0]: 10.1.4.2:49153 remoteaddress[0]: 10.1.6.2:49153 remoteaddress[0]: 10.1.2.2:49153 remoteaddress[0]: 10.1.9.2:49153 remoteaddress[0]: {garbage here} java.lang.NullPointerException at kokuks.KKSAddress.<init>(KKSAddress.java:139) at kokuks.KKSAddress.createAddress(KKSAddress.java:48) at kokuks.KKSSocket._recvFrom(KKSSocket.java:963) at kokuks.scheduler.RecvOperation$1.execute(RecvOperation.java:144) at kokuks.scheduler.RecvOperation$1.execute(RecvOperation.java:1) at kokuks.KKSEvent.run(KKSEvent.java:58) at kokuks.KokuKS.handleJNIEventExpiry(KokuKS.java:872) at kokuks.KokuKS.handleJNIEventExpiry_fjni(KokuKS.java:880) at kokuks.KokuKS.runSimulator_jni(Native Method) at kokuks.KokuKS$1.run(KokuKS.java:773) at java.lang.Thread.run(Thread.java:717) remoteaddress[0]: 10.1.7.2:49153 The null pointer exception comes from trying to use the corrupt string. In C++, the address prints to standard out normally, but doing this reduces the rate of errors, from what I can see. The C++ code (if it helps): /* * Class: kokuks_KKSSocket * Method: recvFrom_jni * Signature: (Ljava/lang/String;[Ljava/lang/String;Ljava/nio/ByteBuffer;IIJ)I */ JNIEXPORT jint JNICALL Java_kokuks_KKSSocket_recvFrom_1jni (JNIEnv *env, jobject obj, jstring sockpath, jobjectArray addrarr, jobject buf, jint position, jint limit, jlong flags) { if (addrarr && env->GetArrayLength(addrarr) > 0) { env->SetObjectArrayElement(addrarr, 0, NULL); } jboolean iscopy; const char* cstr = env->GetStringUTFChars(sockpath, &iscopy); std::string spath = std::string(cstr); env->ReleaseStringUTFChars(sockpath, cstr); // release me! if (KKS_DEBUG) { std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << std::endl; } ns3::Ptr<ns3::Socket> socket = ns3::Names::Find<ns3::Socket>(spath); if (!socket) { std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << " socket not found for path!!" << std::endl; return -1; // not found } if (!addrarr) { std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << " array to set sender is null" << std::endl; return -1; } jsize arrsize = env->GetArrayLength(addrarr); if (arrsize < 1) { std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << " array too small to set sender!" << std::endl; return -1; } uint8_t* bufaddr = (uint8_t*)env->GetDirectBufferAddress(buf); long bufcap = env->GetDirectBufferCapacity(buf); uint8_t* realbufaddr = bufaddr + position; uint32_t remaining = limit - position; if (KKS_DEBUG) { std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << " bufaddr: " << bufaddr << ", cap: " << bufcap << std::endl; } ns3::Address aaddr; uint32_t mflags = flags; int ret = socket->RecvFrom(realbufaddr, remaining, mflags, aaddr); if (ret > 0) { if (KKS_DEBUG) std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << " addr: " << aaddr << std::endl; ns3::InetSocketAddress insa = ns3::InetSocketAddress::ConvertFrom(aaddr); std::stringstream ss; insa.GetIpv4().Print(ss); ss << ":" << insa.GetPort() << std::ends; if (KKS_DEBUG) std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << " addr: " << ss.str() << std::endl; jsize index = 0; const char *cstr = ss.str().c_str(); jstring jaddr = env->NewStringUTF(cstr); if (jaddr == NULL) std::cout << "[kks-c~" << spath << "] " << __PRETTY_FUNCTION__ << " jaddr is null!!" << std::endl; //jaddr = (jstring)env->NewGlobalRef(jaddr); env->SetObjectArrayElement(addrarr, index, jaddr); //if (env->ExceptionOccurred()) { // env->ExceptionDescribe(); //} } jint jret = ret; return jret; } The Java code (if it helps): /** * Pass an array of size 1 into remote address, and this will be set with * the sender of the packet (hax). This emulates C++ references. * * @param remoteaddress * @param buf * @param flags * @return */ public int _recvFrom(final KKSAddress remoteaddress[], ByteBuffer buf, long flags) { if (!kks.isCurrentlyThreadSafe()) throw new RuntimeException( "Not currently thread safe for ns-3 functions!" ); //lock.lock(); try { if (!buf.isDirect()) return -6; // not direct!! final String[] remoteAddrStr = new String[1]; int ret = 0; ret = recvFrom_jni( path.toPortableString(), remoteAddrStr, buf, buf.position(), buf.limit(), flags ); if (ret > 0) { System.out.println("remoteaddress[0]: " + remoteAddrStr[0]); remoteaddress[0] = KKSAddress.createAddress(remoteAddrStr[0]); buf.position(buf.position() + ret); } return ret; } finally { errNo = _getErrNo(); //lock.unlock(); } } public int recvFrom(KKSAddress[] fromaddress, final ByteBuffer bytes, long flags, long timeoutMS) { if (KokuKS.DEBUG_MODE) printMessage("public synchronized int recvFrom(KKSAddress[] fromaddress, final ByteBuffer bytes, long flags, long timeoutMS)"); if (kks.isCurrentlyThreadSafe()) { return _recvFrom(fromaddress, bytes, flags); // avoid event } fromaddress[0] = null; RecvOperation ro = new RecvOperation( kks, this, flags, true, bytes, timeoutMS ); ro.start(); fromaddress[0] = ro.getFrom(); return ro.getRetCode(); }

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  • Android Consistent Crash - NullPointerException

    - by Jesse
    I have tested my app on numerous devices and this never happens, but when I look in my Android Developer Console, I am seeing a lot of these: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.MyApp/com.MyApp.ProductMain}: java.lang.NullPointerException at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1696) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1716) at android.app.ActivityThread.access$1500(ActivityThread.java:124) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:968) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:130) at android.app.ActivityThread.main(ActivityThread.java:3806) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:507) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.NullPointerException at com.MyApp.ProductMain.onCreate(Unknown Source) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1660) ... 11 more To me, this really doesnt tell me much, but maybe someone can read this better than I???

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  • Best way to load application settings

    - by enzom83
    A simple way to keep the settings of a Java application is represented by a text file with ".properties" extension containing the identifier of each setting associated with a specific value (this value may be a number, string, date, etc..). C# uses a similar approach, but the text file must be named "App.config". In both cases, in source code you must initialize a specific class for reading settings: this class has a method that returns the value (as string) associated with the specified setting identifier. // Java example Properties config = new Properties(); config.load(...); String valueStr = config.getProperty("listening-port"); // ... // C# example NameValueCollection setting = ConfigurationManager.AppSettings; string valueStr = setting["listening-port"]; // ... In both cases we should parse strings loaded from the configuration file and assign the ??converted values to the related typed objects (parsing errors could occur during this phase). After the parsing step, we must check that the setting values ??belong to a specific domain of validity: for example, the maximum size of a queue should be a positive value, some values ??may be related (example: min < max), and so on. Suppose that the application should load the settings as soon as it starts: in other words, the first operation performed by the application is to load the settings. Any invalid values for the settings ??must be replaced automatically with default values??: if this happens to a group of related settings, those settings are all set with default values. The easiest way to perform these operations is to create a method that first parses all the settings, then checks the loaded values ??and finally sets any default values??. However maintenance is difficult if you use this approach: as the number of settings increases while developing the application, it becomes increasingly difficult to update the code. In order to solve this problem, I had thought of using the Template Method pattern, as follows. public abstract class Setting { protected abstract bool TryParseValues(); protected abstract bool CheckValues(); public abstract void SetDefaultValues(); /// <summary> /// Template Method /// </summary> public bool TrySetValuesOrDefault() { if (!TryParseValues() || !CheckValues()) { // parsing error or domain error SetDefaultValues(); return false; } return true; } } public class RangeSetting : Setting { private string minStr, maxStr; private byte min, max; public RangeSetting(string minStr, maxStr) { this.minStr = minStr; this.maxStr = maxStr; } protected override bool TryParseValues() { return (byte.TryParse(minStr, out min) && byte.TryParse(maxStr, out max)); } protected override bool CheckValues() { return (0 < min && min < max); } public override void SetDefaultValues() { min = 5; max = 10; } } The problem is that in this way we need to create a new class for each setting, even for a single value. Are there other solutions to this kind of problem? In summary: Easy maintenance: for example, the addition of one or more parameters. Extensibility: a first version of the application could read a single configuration file, but later versions may give the possibility of a multi-user setup (admin sets up a basic configuration, users can set only certain settings, etc..). Object oriented design.

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  • Xubuntu 13.10 64bit - Slow and buggy "log out" process?

    - by MrKatSwordfish
    I'm a Windows convert who has done only a little bit of dabbling in Ubuntu in the past (back in Dapper Drake a few years back). A lot has changes since then, and I've been yearning to jump back into linux again! So, having just bought a new SSD, I felt that this would be as good of a time as any to set up a dual-boot system again. I've messed around with Ubuntu 13.10 a bit, and while Unity has its issues, I think that it still needs some time to develop. I looked into XFCE and liked it a lot, so I went with Xubuntu. I've installed Xubuntu, and for the most part it's running smoothly and it a pleasure to work with. The customization is great and the minimalistic look and feel is really nice! But here's my problem, whenever I select the "Log Out" option from either the application menu, or the user profiles menu, my PC comes to a crawl, and the dialog box with all the options (shut down, restart, log out, etc.) takes maybe a minute or more to appear. I click the log out button, my PC is brought to a snail's pace, and I have to wait for what seems like an eternity for the logout options to appear! If i try to open something else (even a terminal window) while it's loading the logout options, that other program won't finish loading until the logout screen finally appears. Keep in mind, this is a pretty much vanilla install of Xubuntu 13.10 64bit, on a PC with an intel i7, an SSD, 6gb DDR3 RAM, and a new AMD 7770 gpu (drivers haven't been installed yet, though). Everything else runs fast, most applications open near-instantly! It must be an issue with how the logout options screen initializes or something, but I'm not sure exactly how I can fix it.. Edit - Extra Info: This problem is very consistent when using the "Log Out" buttons in Xubuntu. However, I've found that I'm able to reboot and shutdown much more quickly by going through the "Switch User" screen, and using the reboot or shutdown buttons on that screen. I'm nearly certain that it has something to do with the little Log Out options screen that appears when I select Log Out from the menu, and not the actual process of shutting down.. So what should I do? I really like XFCE so far, and I've never tried a non-ubuntu based distro before, but should I just switch to something else? Is there any known fix for this issue? Are there any work-arounds for logging out/shutting down/rebooting via the terminal so that I can avoid this irritating bug? Is there any that I can monitor the progress of the log out via terminal, allowing me to see which parts are causing the slow-down? What is the best way to report this bug to someone?

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  • "Attach to native process failed" with Apache 2.0 Agent 2.202 for RHEL5 Linux 64bit

    - by Richard
    In trying to install Apache 2.0 Agent 2.202 for RHEL5 Linux 64bit, the dialogue appears as follows. # export JAVAHOME=/usr/java/jdk1.6.0_24/; echo $JAVAHOME /usr/java/jdk1.6.0_24/ # ./setup Launching installer... Attach to native process failed On the server we have the following JREs and I've tried both. $ sudo rpm -qa | egrep "(openjdk|icedtea)" java-1.6.0-openjdk-1.6.0.0-1.27.1.10.8.el5_8 And SElinux appears to be off: # cat /etc/sysconfig/selinux SELINUX=disabled SELINUXTYPE=targeted

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