03106: | ConnectorClassJarer does not copy entire .class files |
Category: Connector
Status: ClosedSeverity: HIGH
Reported against release: 0.8
Fixed in release: 0.8.2 (Beta Refresh 2)
PROBLEM:com.mot.openwings.connector.ConnectorClassJarer uses
InputStream.available to determine how may bytes are in the stream.
However, available() only returns the number of bytes currently
available to read, hence the current implementation could copy partial
files instead of whole files.
NOTE:
This defect was first written based on code review comments. It was not
actually observed until connector generation was performed on Solaris
and Linux platforms. The problem occurred intermittently and the
symptom is that a java.lang.ClassFormatError is thrown when the
connector is being loaded. ANALYSIS:The ConnectorClassJarer copies classes that the interface is dependent
on into the connector jar file. For each class, the ConnectorClassJarer
obtains an input stream, allocates a byte array where the length is
determined by InputStream.available(), reads into the array, and then
writes the array to the connector jar file.
Usually available() returns the number of bytes in the file, but when
the class is located in a .class or .jar file on a mounted filesystem,
this may not be the case. What happens is that the JarEntry is written
to the JarFile with the correct length, but fewer bytes may be written
to the stream depending on what is returned from available(). The the
JarEntry is closed. When you unzip the resulting jar file and look at
the .class files, they have the right length, but if you look at them
in a hex editor, you'll see that the .class file ends in 0's.
This is an error-prone algorithm and should be corrected so as not to
rely on available(). WORKAROUND:Make sure that all classes that your connector interface depends on are
available in files on the local (not mounted) filesystem. Also, this
problem has only been observed on UNIX platforms, so try building your
connectors on Windows.
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