java IO Exception: Stream Closed

Question

This is the code I currently have:

public class FileStatus extends Status{ FileWriter writer; public FileStatus(){     try {         writer = new FileWriter("status.txt",true);     } catch (IOException e) {          e.printStackTrace();     }  }  public void writeToFile(){     String file_text= pedStatusText + "     " + gatesStatus + "     " + DrawBridgeStatusText;     try {         writer.write(file_text);         writer.flush();         writer.close();     } catch (IOException e) {         // TODO Auto-generated catch block         e.printStackTrace();     } } } 

Everything works as expected (The file is written to when the writeToFile method is called). However when the writeToFile method is called a second time I get the following error:

    java.io.IOException: Stream closed     at sun.nio.cs.StreamEncoder.ensureOpen(StreamEncoder.java:45)     at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:118)     at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:135)     at java.io.OutputStreamWriter.write(OutputStreamWriter.java:220)     at java.io.Writer.write(Writer.java:157)     at FileStatus.writeToFile(FileStatus.java:19)     at MenuBar$9.actionPerformed(MenuBar.java:115)     at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)     at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)     at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)     at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)     at javax.swing.AbstractButton.doClick(AbstractButton.java:376)     at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)     at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)     at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)     at java.awt.Component.processMouseEvent(Component.java:6505)     at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)     at java.awt.Component.processEvent(Component.java:6270)     at java.awt.Container.processEvent(Container.java:2229)     at java.awt.Component.dispatchEventImpl(Component.java:4861)     at java.awt.Container.dispatchEventImpl(Container.java:2287)     at java.awt.Component.dispatchEvent(Component.java:4687)     at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)     at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)     at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)     at java.awt.Container.dispatchEventImpl(Container.java:2273)     at java.awt.Window.dispatchEventImpl(Window.java:2719)     at java.awt.Component.dispatchEvent(Component.java:4687)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:703)     at java.awt.EventQueue.access$000(EventQueue.java:102)     at java.awt.EventQueue$3.run(EventQueue.java:662)     at java.awt.EventQueue$3.run(EventQueue.java:660)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)     at java.awt.EventQueue$4.run(EventQueue.java:676)     at java.awt.EventQueue$4.run(EventQueue.java:674)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:673)     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)     at java.awt.EventDispatchThread.run(EventDispatchThread.java:97) java.io.IOException: Stream closed     at sun.nio.cs.StreamEncoder.ensureOpen(StreamEncoder.java:45)     at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:118)     at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:135)     at java.io.OutputStreamWriter.write(OutputStreamWriter.java:220)     at java.io.Writer.write(Writer.java:157)     at FileStatus.writeToFile(FileStatus.java:19)     at MenuBar$9.actionPerformed(MenuBar.java:115)     at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)     at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)     at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)     at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)     at javax.swing.AbstractButton.doClick(AbstractButton.java:376)     at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)     at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)     at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)     at java.awt.Component.processMouseEvent(Component.java:6505)     at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)     at java.awt.Component.processEvent(Component.java:6270)     at java.awt.Container.processEvent(Container.java:2229)     at java.awt.Component.dispatchEventImpl(Component.java:4861)     at java.awt.Container.dispatchEventImpl(Container.java:2287)     at java.awt.Component.dispatchEvent(Component.java:4687)     at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)     at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)     at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)     at java.awt.Container.dispatchEventImpl(Container.java:2273)     at java.awt.Window.dispatchEventImpl(Window.java:2719)     at java.awt.Component.dispatchEvent(Component.java:4687)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:703)     at java.awt.EventQueue.access$000(EventQueue.java:102)     at java.awt.EventQueue$3.run(EventQueue.java:662)     at java.awt.EventQueue$3.run(EventQueue.java:660)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)     at java.awt.EventQueue$4.run(EventQueue.java:676)     at java.awt.EventQueue$4.run(EventQueue.java:674)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:673)     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)     at java.awt.EventDispatchThread.run(EventDispatchThread.java:97) java.io.IOException: Stream closed     at sun.nio.cs.StreamEncoder.ensureOpen(StreamEncoder.java:45)     at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:118)     at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:135)     at java.io.OutputStreamWriter.write(OutputStreamWriter.java:220)     at java.io.Writer.write(Writer.java:157)     at FileStatus.writeToFile(FileStatus.java:19)     at MenuBar$9.actionPerformed(MenuBar.java:115)     at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)     at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)     at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)     at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)     at javax.swing.AbstractButton.doClick(AbstractButton.java:376)     at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:833)     at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:877)     at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)     at java.awt.Component.processMouseEvent(Component.java:6505)     at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)     at java.awt.Component.processEvent(Component.java:6270)     at java.awt.Container.processEvent(Container.java:2229) 

the file is still written to the second time as expected but it throws this error on the second and future calls to writeToFile(). I am wondering what is causing this error to happen.

Answer 1

You're calling writer.close(); after you've done writing to it. Once a stream is closed, it can not be written to again. Usually, the way I go about implementing this is by moving the close out of the write to method.

public void writeToFile(){     String file_text= pedStatusText + "     " + gatesStatus + "     " + DrawBridgeStatusText;     try {         writer.write(file_text);         writer.flush();     } catch (IOException e) {         // TODO Auto-generated catch block         e.printStackTrace();     } } 

And add a method cleanUp to close the stream.

public void cleanUp() {      writer.close(); } 

This means that you have the responsibility to make sure that you're calling cleanUp when you're done writing to the file. Failure to do this will result in memory leaks and resource locking.

EDIT: You can create a new stream each time you want to write to the file, by moving writer into the writeToFile() method..

 public void writeToFile() {     FileWriter writer = new FileWriter("status.txt", true);     // ... Write to the file.      writer.close();  } 

Answer 2

You call writer.close(); in writeToFile so the writer has been closed the second time you call writeToFile.

Why don't you merge FileStatus into writeToFile?