Question

I’m using a BufferedWriter to write some data to a textfile. It’s faster than using ODBC to write to Access. Code looks something like this:

BufferedWriter bw = new BufferedWriter(new FileWriter(new File(filePath), true));

True is to make the BufferedWriter append, not overwrite.

bw.append(          
    country + "\t" +
    scenario + "\t" +
    tempStage + "\t" +
    year + "\t" +
    tempState
);

It’s worked for me in previous projects. New problem: it just craps out in the middle of the line. This is a good line:

SultanateOfBrunei   BeeBeeScenario  Other   2019

The last line typically looks like this:

SultanateOfBrunei   BeeBeeScenario  Other   2019 Nondyna

or
Sulta

or even
Su

I put in error handling code to ignore weird incomplete lines like that.

This means not all the data is being written. I can give up one datum, no problem… But it appears to be cutting out more. The simulation runs 1990 to the end of 2020 and it typically craps out somewhere in 2019. Increasing the VM helps a little– it gets further. But I only have a certain amount of memory!

Any insights?

Thanks!!

Answer 1

Your application is probably not closing the BufferedWriter, and as a result the last part of the output is not being written out to the file.

The structure of your program should be something like this:

BufferedWriter bw = new BufferedWriter(new FileWriter(new File(filePath), true));
try {
    // generate output
} finally {
    bw.close();
}

Note that this doesn’t attempt to handle the I/O exceptions that might arise while opening, writing to or closing the writer. Whether you should do that, and what you should do with any exceptions that you catch depends on the circumstances.