Can you make FilePrinter.java appendLog() to catch Exception?

[jclova]

void appendLog(String flattenedLog) {
try {
bufferedWriter.write(flattenedLog);
bufferedWriter.newLine();
bufferedWriter.flush();
} catch (IOException e) {
}
}

Can you change catch IOException to Exception?

I am getting many following NullPointerException
Fatal Exception: java.lang.NullPointerException
Attempt to invoke virtual method 'void java.io.Writer.write(java.lang.String)' on a null object reference
com.elvishew.xlog.printer.file.FilePrinter$Writer.appendLog (FilePrinter.java:481)

As the application trying to initialize XLog, there are some logs being logged concurrently.
Some logs are being written even before bufferedWriter is initialized.

[elvishew]

@jclova Have you modified the xlog library's source code, like set the FilePrinter#USE_WORKER to false?

By default, USE_WORKER is set to true, and we use a worker, which is thread-safe, to print the log, so no worry about being logged concurrently. But if you set USE_WORKER to false, then something wrong may happen.

Besides, as what you said "Some logs are being written even before bufferedWriter is initialized.", no worry, if you use XLog to log, an exception will be thrown if you haven't init xlog.

[jclova]

No, I did not FilePrinter#USE_WORKER to false.
I have looked into your source code too and I don't see any cases that it will throw an error.
However, in reality I have a bunch of user crashes reported to my Crashlytics.

[jclova]

btw, this is what my init method looks like:

`public static void init(Context context, boolean isDebug) {
Printer androidPrinter = new AndroidPrinter();
filePrinter = new FilePrinter
.Builder(context.getFilesDir().getAbsolutePath() + "/xlog/")
.backupStrategy(new NeverBackupStrategy())
.build();

    LogConfiguration config = new LogConfiguration.Builder()
            .logLevel(isDebug ?
                      LogLevel.ALL
                              :
                      LogLevel.INFO)
            .tag(DEFAULT_TAG)
            .build();
    XLog.init(config,
            androidPrinter,
            filePrinter);

    XLog.d("*** Application start ***");
}`

[elvishew]

Finally figured out the root reason:
Before the log-to-file worker started, if there are several logging requests from different threads come in together, the worker may be started several times, that results multiple writing thread, and singleton isn't guaranteed any more.

Make sure only one writing thread, the crash should be resolved

Please update to v1.8.0 ASAP, and sorry for letting this issue existing so long