[jira] Closed: (HARMONY-479) java.io.FileInputStream and FileOutputStream might cause Finalizer thread suspending

["George Harley (JIRA)" <ji...@apache.org>]

     [ http://issues.apache.org/jira/browse/HARMONY-479?page=all ]
     
George Harley closed HARMONY-479:
---------------------------------


Verified by Paulex. 

> java.io.FileInputStream and FileOutputStream might cause Finalizer thread suspending
> ------------------------------------------------------------------------------------
>
>          Key: HARMONY-479
>          URL: http://issues.apache.org/jira/browse/HARMONY-479
>      Project: Harmony
>         Type: Bug

>   Components: Classlib
>     Reporter: Paulex Yang
>     Assignee: George Harley
>  Attachments: Harmony-479.diff
>
> If one FileInputStream instance is not constructed properly, say, the given file doesn't exist, the constructor will throw exception but the FileInputStream instance is still necessary to be garbage collected, and the spec of FileInputStream's finalize() method requires that close() must be invoked, but the current implementation of FileInputStream.close()(as below) will causes NullPointerException in Finalizer thread because channel field has not been initialized yet.
>     public void close() throws IOException {
>             synchronized (channel) {
>                 synchronized (this) {
>                     if (channel.isOpen() && fd.descriptor >= 0) {
>                         channel.close();
>                     }
>                     fd.descriptor = -1;
>                 }
>             }
>     }
> This issue applies to FileOutputStream, too. Test case below can reproduce this issue only in debugger, because it is not easy to get the handle of Finalizer thread. Debugging the test case to the statement following the System.gc(), the debugger will show that the Finalizer thread is suspended due to NullPointerException.
> public class FileInputStreamTest {
>     public static void main(String[] args) throws Exception{
>         FileInputStream is = null;
>         try{
>             is = new FileInputStream(new File("nonexist"));
>         }catch(Exception e){
>             System.gc();
>             e.printStackTrace();
>         }
>     }
> }

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