I have this Java application in which I am now developing a module that can read and execute SQL statements from a file and output the results of the queries. If I launch the module via its main method, it works fine. I give the path to the DB connection settings file (with the user, pass, port.. etc), the path to a file containing SQL queries and the name of the output file. As I said, launched as stand alone, it works fine, connects with no problem, executes queries and outputs their results.
If I integrate it in the application workflow, it fails to connect to the database, even if the credentials (i.e., DB connection settings file) are the same. I have tried to wrap it around in a thread, tried to search if I need to launch the connection asynchronously, but nothing helped. The mysql-connector-java-5.1.28 is in the classpath, everything looks fine. I have also tried to set the autoReconnect (the commented line) but it also fails. This is the code to create the connection:
String url = "jdbc:mysql://"+server+":3306/?useCursorFetch=true";
//String url = "jdbc:mysql://"+server+":3306/?autoReconnect=true";
try {
return DriverManager.getConnection(url, user, password);
} catch (SQLException e1) {
Logging.outputStackTrace(e1);
throw new RuntimeException("Cannot connect to DB server: " + e1.getMessage());
with server = localhost. The user and pass are fine, sorry for repeating a third time, the connection is successful while launching it via the module's main method.
This is the stack trace I get while running the module via the application:
ERROR: An error occurred : Could not create connection to database server. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
Check the error log for details
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
java.lang.reflect.Constructor.newInstance(Unknown Source)
com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
com.mysql.jdbc.Util.getInstance(Util.java:386)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1015)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920)
com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2575)
com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2311)
com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
java.lang.reflect.Constructor.newInstance(Unknown Source)
com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:347)
java.sql.DriverManager.getConnection(Unknown Source)
java.sql.DriverManager.getConnection(Unknown Source)
org.application.utilities.DBConnection.connectToMySQL(DBConnection.java:144)
org.application.utilities.DBConnection.connect(DBConnection.java:107)
org.application.utilities.RunSQL.run(RunSQL.java:110)
org.application.workflow.Processing.extractData(Processing.java:201)
org.application.workflow.Processing.<init>(Processing.java:73)
org.application.gui.ApiGUI$2.actionPerformed(ApiGUI.java:349)
javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
javax.swing.DefaultButtonModel.setPressed(Unknown Source)
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
java.awt.Component.processMouseEvent(Unknown Source)
javax.swing.JComponent.processMouseEvent(Unknown Source)
java.awt.Component.processEvent(Unknown Source)
java.awt.Container.processEvent(Unknown Source)
java.awt.Component.dispatchEventImpl(Unknown Source)
java.awt.Container.dispatchEventImpl(Unknown Source)
java.awt.Component.dispatchEvent(Unknown Source)
java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
java.awt.Container.dispatchEventImpl(Unknown Source)
java.awt.Window.dispatchEventImpl(Unknown Source)
java.awt.Component.dispatchEvent(Unknown Source)
java.awt.EventQueue.dispatchEventImpl(Unknown Source)
java.awt.EventQueue.access$200(Unknown Source)
java.awt.EventQueue$3.run(Unknown Source)
java.awt.EventQueue$3.run(Unknown Source)
java.security.AccessController.doPrivileged(Native Method)
java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
java.awt.EventQueue$4.run(Unknown Source)
java.awt.EventQueue$4.run(Unknown Source)
java.security.AccessController.doPrivileged(Native Method)
java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
java.awt.EventQueue.dispatchEvent(Unknown Source)
java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
java.awt.EventDispatchThread.pumpEvents(Unknown Source)
java.awt.EventDispatchThread.pumpEvents(Unknown Source)
java.awt.EventDispatchThread.run(Unknown Source)
Any ideas why this is happening? Is this a thread related issue? Can the event manager of the GUI have something to do with it? There are no multiple connections or concurrent connections to the database. Only once and it is properly closed when done. Via MySQL command line I cal also access my database, I made sure the server is on everytime, etc...
Thank you.
i think you forgot to mention database name
String url = "jdbc:mysql://"+server+":3306/?useCursorFetch=true";
must be
String url = "jdbc:mysql://"+server+":3306/DB_NAME?useCursorFetch=true";
OK. Got it. When I was running the SQL module via the application, I was setting the file encoding to ANSI via
System.setProperty("file.encoding", "ANSI");
which was not the case while running it stand alone.
Apparently the DriverManager.getConnection(url, user, pass) does not set the character set on its own to make sure it sends requests in a compatible character encoding. Maybe that should be fixed in the java.sql package.
Related
I am facing a strange situation with my java swing application. In my pc(win-7 x64 and jre-7), it is working fine.I am able to run the jar file on my system, but on a windows xp machine with jre7 installed, it gives the following error trace:
C:\Documents and Settings\HOME\Desktop\TweetTweetAsMuchYouTweet_jar>java -jar Tw
eetTweetAsMuchYouTweet.jar
401:Authentication credentials (https://dev.twitter.com/pages/auth) were missing
or incorrect. Ensure that you have set valid consumer key/secret, access token/
secret, and the system clock is in sync.
Failed to validate oauth signature and token
Relevant discussions can be found on the Internet at:
http://www.google.co.jp/search?q=10f5ada3 or
http://www.google.co.jp/search?q=0276a2ab
TwitterException{exceptionCode=[10f5ada3-0276a2ab], statusCode=401, message=null
, code=-1, retryAfter=-1, rateLimitStatus=null, version=3.0.5}
at twitter4j.internal.http.HttpClientImpl.request(HttpClientImpl.java:16
2)
at twitter4j.internal.http.HttpClientWrapper.request(HttpClientWrapper.j
ava:61)
at twitter4j.internal.http.HttpClientWrapper.post(HttpClientWrapper.java
:98)
at twitter4j.auth.OAuthAuthorization.getOAuthRequestToken(OAuthAuthoriza
tion.java:122)
at twitter4j.auth.OAuthAuthorization.getOAuthRequestToken(OAuthAuthoriza
tion.java:104)
at twitter4j.TwitterBaseImpl.getOAuthRequestToken(TwitterBaseImpl.java:2
98)
at Account.getAccessTokenAfterAuthentication(Account.java:45)
at Account.<init>(Account.java:33)
at AddFormWin$1.actionPerformed(AddFormWin.java:75)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Sour
ce)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
If we note the line:
Authentication credentials (https://dev.twitter.com/pages/auth) were missing
or incorrect. Ensure that you have set valid consumer key/secret, access token/
secret, and the system clock is in sync.
Failed to validate oauth signature and token
The authentication is failing due to invalid consumer key/secret. But then why the same app on windows 7 machine, is running perfectly?
Note that in my app, I am using the oob(PIN based) authentication using Twitter4j(v-3.0.5).
Being a java developer myself, I am quiet surprised with this as java is known for its platform independence. So is there anything wrong with the platform independence of java?
This doesn't look like Java VM or Windows OS issue. I would suspect there is something to do with oob implementation or the wrong PIN was entered. I assume the PIN needs to be entered for each machine.
We have a client server application which runs using spring remoting framework and we are using jetty server and Java 1.7. We deliver both client and server to the customers.
At one of customer's office, for one of the user login, he is getting this Exception which is mentioned in the title of the postjava.net.SocketException:Unexpected end of file from the server. He is actually doing the search for something which makes a server call and finally he ends up getting this error in the error log.
The weird thing is, nobody else in the Customer's office gets this error. It is very weird.
And also i googled about this exception but did not get appropriate answer.
Please provide your suggestions.
org.springframework.remoting.RemoteAccessException: Could not access HTTP invoker remote service at [http://192.168.13.211:6094/SearchFieldServer]; nested exception is ava.net.SocketException: Unexpected end of file from server at org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor.convertHttpInvokerAccessException(HttpInvokerClientInterceptor.java:211)
at org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor.invoke(HttpInvokerClientInterceptor.java:144)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy69.search(Unknown Source)
at se.transware.awt.SearchFieldModel.setObjectIdAndReload(SearchFieldModel.java:329)
at se.transware.awt.SearchFieldModel.setObjectIdAndReload(SearchFieldModel.java:293)
at se.transware.awt.SearchFieldModel.setObjectID(SearchFieldModel.java:282)
at se.transware.awt.SearchField.setOid(SearchField.java:740)
at se.transware.tt.client.register.CustomerClientRegGUI.load(CustomerClientRegGUI.java:3885)
at se.transware.tt.client.register.CustomerClientRegLogic.pseudoConstructor(CustomerClientRegLogic.java:786)
at se.transware.tt.client.main.ModuleController.flipApp(ModuleController.java:222)
at se.transware.tt.client.main.SystemResources.flipApp(SystemResources.java:260)
at se.transware.tt.client.register.RegObjectsTableLogicClientAdapter.editRegObject(RegObjectsTableLogicClientAdapter.java:511)
at se.transware.tt.client.register.RegObjectsTable2$18.mouseClicked(RegObjectsTable2.java:1150)
at java.awt.AWTEventMulticaster.mouseClicked(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.net.SocketException: Unexpected end of file from server
at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)
at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.net.HttpURLConnection.getResponseCode(Unknown Source)
at org.springframework.remoting.httpinvoker.SimpleHttpInvokerRequestExecutor.validateResponse(SimpleHttpInvokerRequestExecutor.java:138)
at org.springframework.remoting.httpinvoker.SimpleHttpInvokerRequestExecutor.doExecuteRequest(SimpleHttpInvokerRequestExecutor.java:62)
at org.springframework.remoting.httpinvoker.AbstractHttpInvokerRequestExecutor.executeRequest(AbstractHttpInvokerRequestExecutor.java:134)
at org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor.executeRequest(HttpInvokerClientInterceptor.java:191)
at org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor.executeRequest(HttpInvokerClientInterceptor.java:173)
at org.springframework.remoting.httpinvoker.HttpInvokerClientInterceptor.invoke(HttpInvokerClientInterceptor.java:141)
... 45 more
Here are some links which you probably already found :
https://forums.oracle.com/forums/thread.jspa?messageID=7076649
http://www.coderanch.com/t/207583/sockets/java/java-net-SocketException-Unexpected-file
http://cxf.547215.n5.nabble.com/Caused-by-java-net-SocketException-Unexpected-end-of-file-from-server-td4715340.html
Additionally, if you can share some code snippet or stack trace we can share more realistic comments on this issue. Maybe it is caused by some security options of the client facing this issue.
Are all customers configuration the same?
I am making an applet that connects to a database that is stored on the same web server, and when I test the code in the applet viewer in Eclipse, it connects. Problem is, when I try to run it outside Eclipse (on web server or locally), I get this error:
Exception in thread "AWT-EventQueue-2" java.lang.ExceptionInInitializerError
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:286)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.j_ctrl.MovePanel.connectDB(MovePanel.java:569)
at com.j_ctrl.MovePanel.showHighScore(MovePanel.java:558)
at com.j_ctrl.MovePanel.enterPress(MovePanel.java:544)
at com.j_ctrl.MovePanel$1.keyPressed(MovePanel.java:163)
at java.awt.Component.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.security.AccessControlException: access denied (java.util.PropertyPermission file.encoding read)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)
at java.lang.System.getProperty(Unknown Source)
at com.mysql.jdbc.StringUtils.<clinit>(StringUtils.java:70)
... 39 more
Is there anything special that needs to be done in order to connect to an SQL database from an applet?
Here is the code that handles the connection:
private void connectDB(){
try{
String driverName = "com.mysql.jdbc.Driver";
Class.forName(driverName);
String url = "jdbc:mysql://localhost/database";
String user = "user";
String pass = "pass";
connection = DriverManager.getConnection(url, user, pass);
System.out.println("Connected");
}catch(Exception ex){
ex.printStackTrace();
}
}
I changed the username, password and database here, but in my code they are correct.
Edit
Since connecting to the SQL server didn't work (I imagine it was hosted on a different host), I have ended up changing the way I access the database. The applet opens a connection to a PHP file on the host, which in turn connects to the database. Either way this is more secure.
This is being caused by the security model for applets. Here's a good article summarizing the two main ways around this issue - either sign the applet or use a policy file. Let us know if you still experience problems after trying one of these:
http://www.coderanch.com/how-to/java/HowCanAnAppletReadFilesOnTheLocalFileSystem
You need to sign your applet. Here is some good documentation on how.
I'm trying to launch my applet locally and this is the exception I get:
I don't know why this is happening the mp3 is already located on the jar file, why can't I access it?
SEVERE: null
java.security.AccessControlException: access denied (java.io.FilePermission file:\C:\applet\CairoNightTrainClient.jar!\Music\train.mp3 read)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkRead(Unknown Source)
at java.io.FileInputStream.<init>(Unknown Source)
at com.sun.media.codec.audio.mp3.JS_MP3FileReader.getAudioInputStream(JS_MP3FileReader.java:113)
at javax.sound.sampled.AudioSystem.getAudioInputStream(Unknown Source)
at LogicEngine.DJ.createClip(DJ.java:56)
at LogicEngine.DJ.<init>(DJ.java:42)
at GUI.JPanelGameApplet$1.run(JPanelGameApplet.java:65)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Applets (or at least untrusted applets) are not allowed to access the local file system. This is kind of a good thing as most people might get upset if random websites had such access.
If you want to access a file go through javax.jnlp (just google it) and it'll provide an API that presents the user with a file chooser to allow applets to read a specific file of their choosing.
If it's just a file that is part of the applet, use either a resource (Class.getResourceAsStream) or through an http connection (URL)
My app seems to be hanging overnight because of the connection getting dropped(I think that's the problem.) How can I structure my app so that it can try to roll up a new connection?
Since the incident I have updated the getConnection() method that my app uses as so:
private Connection getConnection() {
boolean failed = false;
try{
failed = !connection.isValid(1000);
}catch(SQLException ex){
System.out.println("WARNING: Connection not valid!");
}
try{
failed = connection.isClosed();
}catch(SQLException ex){
System.out.println("WARNING: Connection is closed!");
}
if(failed){
System.out.println("Renewing connection");
this.initializeConnection();
}
return connection;
}
This is the output:
** BEGIN NESTED EXCEPTION **
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException
MESSAGE: The last packet successfully received from the server was54521 seconds
ago.The last packet sent successfully to the server was 54521 seconds ago, which
is longer than the server configured value of 'wait_timeout'. You should consi
der either expiring and/or testing connection validity before use in your applic
ation, increasing the server configured values for client timeouts, or using the
Connector/J connection property 'autoReconnect=true' to avoid this problem.
STACKTRACE:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet success
fully received from the server was54521 seconds ago.The last packet sent success
fully to the server was 54521 seconds ago, which is longer than the server conf
igured value of 'wait_timeout'. You should consider either expiring and/or testi
ng connection validity before use in your application, increasing the server con
figured values for client timeouts, or using the Connector/J connection property
'autoReconnect=true' to avoid this problem.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Sou
rce)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1
074)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3246)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1917)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2536)
at com.mysql.jdbc.ConnectionImpl.setCatalog(ConnectionImpl.java:4962)
at com.mysql.jdbc.DatabaseMetaData.getCallStmtParameterTypes(DatabaseMet
aData.java:1506)
at com.mysql.jdbc.DatabaseMetaData.getProcedureOrFunctionColumns(Databas
eMetaData.java:4120)
at com.mysql.jdbc.DatabaseMetaData.getProcedureColumns(DatabaseMetaData.
java:4057)
at com.mysql.jdbc.CallableStatement.determineParameterTypes(CallableStat
ement.java:809)
at com.mysql.jdbc.CallableStatement.<init>(CallableStatement.java:609)
at com.mysql.jdbc.JDBC4CallableStatement.<init>(JDBC4CallableStatement.j
ava:46)
at sun.reflect.GeneratedConstructorAccessor6.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Sou
rce)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.CallableStatement.getInstance(CallableStatement.java:5
05)
at com.mysql.jdbc.ConnectionImpl.parseCallableStatement(ConnectionImpl.j
ava:3881)
at com.mysql.jdbc.ConnectionImpl.prepareCall(ConnectionImpl.java:3965)
at com.mysql.jdbc.ConnectionImpl.prepareCall(ConnectionImpl.java:3939)
at com.protocase.hmiclient.db.HMIDatabaseAdapter.getAvailableBatchesForW
orkstation(HMIDatabaseAdapter.java:471)
at com.protocase.hmiclient.views.WorkstationContainer.getBatches(Worksta
tionContainer.java:74)
at com.protocase.hmiclient.views.BatchList.<init>(BatchList.java:55)
at com.protocase.hmiclient.views.WorkstationContainer.goToBatchList(Work
stationContainer.java:56)
at com.protocase.hmiclient.views.forms.BatchListControlPanel.refreshButt
onActionPerformed(BatchListControlPanel.java:118)
at com.protocase.hmiclient.views.forms.BatchListControlPanel.access$200(
BatchListControlPanel.java:16)
at com.protocase.hmiclient.views.forms.BatchListControlPanel$3.actionPer
formed(BatchListControlPanel.java:64)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Sour
ce)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown
Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown
Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown
Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.net.SocketException: Software caused connection abort: socket wr
ite error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(Unknown Source)
at java.net.SocketOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.flush(Unknown Source)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3227)
... 61 more
** END NESTED EXCEPTION **
This exception suggests that you're opening the connection only once during application's startup and keeping forever open during the application's lifetime. This is bad. The DB will reclaim the connection sooner or later because it's been open for too long. You should close connections properly in the finally block of the very same try block as you're opening it and executing the query on it.
E.g.
public Entity find(Long id) throws SQLException {
Connection connection = null;
// ...
try {
connection = database.getConnection();
// ...
} finally {
// ...
if (connection != null) try { connection.close(); } catch (SQLException logOrIgnore) {}
}
return entity;
}
If you have a performance concern regarding this (which is very reasonable as connecting is the most expensive task), then you should be using a connection pool. It also transparently handles this kind of "connection dropped" problems. For example, BoneCP. Please note that also in case of a connection pool, you should still be closing the connections in the finally block as per the above JDBC code idiom. It will namely make them available for reuse.