Thread: java.io.EOFException

I am new to java programming and have encountered the following error. I'd greatly appreciate advice and assistance in resolving this exception.

The exception...

java.io.EOFException
at java.io.DataInputStream.readUnsignedShort(DataInpu tStream.java:340)
at com.digitaldan.jomnilinkII.MessageFactory.objectSt atus(MessageFactory
.java:393)
at com.digitaldan.jomnilinkII.MessageFactory.fromByte s(MessageFactory.ja
va:131)
at com.digitaldan.jomnilinkII.Connection.sendAndRecei ve(Connection.java:
275)
at com.digitaldan.jomnilinkII.Connection.reqObjectSta tus(Connection.java
:640)
at com.digitaldan.jomnilinkII.Connection.reqObjectSta tus(Connection.java
:570)
at com.digitaldan.jomnilinkII.examples.Main.main(Main .java:182)

Listing of the referenced lines...

MessageFactory.java line 393
case Message.OBJ_TYPE_UNIT:{
393 ==> status[i] = new UnitStatus(in.readUnsignedShort(),
in.readUnsignedByte(),in.readUnsignedShort());

MessageFactory. java line 131
case Message.MESG_TYPE_EXT_OBJ_STATUS:
131 ==> return (ExtendedObjectStatus)objectStatus(in,len,true);

Connection.java line 275
writeLock.notifyAll();
275 ==> return MessageFactory.fromBytes(ret.data());

Connection.java line 640
640 ==> msg = sendAndReceive(new ReqExtenedObjectStatus(objectType,current,next));

Connection.java 570
public ObjectStatus reqObjectStatus(int objectType, int startObject, int endObject) throws IOException, OmniNotConnectedException, OmniInvalidResponseException, OmniUnknownMessageTypeException
{
570 ==> return reqObjectStatus(objectType,startObject,endObject,f alse);


Main.java line 182
182 ==> ObjectStatus status = c.reqObjectStatus(Message.OBJ_TYPE_UNIT,1,max_unit s);

Welcome to the forum! Please read this topic to learn how to post code in code or highlight tags and other useful info for new members.

Are you trying to read past the end of a file? If so, don't. If you don't think that's the error, then you're going to have to show us more code so that we can see what the code is doing before this error occurs and what it's trying to do that is causing the error.

The code I am using can be found at https://code.google.com/p/jomnilink/ This is code that accesses a security controller. Code compiles successfully. But executing the code produces the above errors.

Specifically, the code queries the controller and displays all the internal information such as security zone names and status of the zones etc. The code isn't reading any type of file such as a database file or text file.

The code is reading something, and it has tried to read beyond the available data.

This is my opinion, not anybody else's or this site's: When you borrow someone else's code for your own application, you assume total responsibility for making it suitable for your application. A factor in one's decision to use someone else's code should include whether the author of the code is available and willing to help with its adoption and the quality of the documentation available to understand and modify the code as needed to fit the desired application.

If the author isn't willing, the documentation is poor, or the code is beyond your abilities to understand and modify, then perhaps you've borrowed the wrong code.

Problem resolved. Using the above posted stack trace led me to line 182 in Main java which is..

ObjectStatus status = c.reqObjectStatus(Message.OBJ_TYPE_UNIT,1,max_units);

The max_units variable was initialized to 511 but it should have been initialized to a max value of 510. Thus, the 511 value was generating the error.

The best way to handle this would be to terminate your infinite loop with a proper condition.

But since you asked for the exception handling:

Try to use two catches. Your EOFException is expected, so there seems to be no problem when it occures. Any other exception should be handled.

...
} catch (EOFException e) {
// ... this is fine
} catch(IOException e) {
// handle exception which is not expected
e.printStackTrace();
}