stanfordnlp/CoreNLP · warning

Exception: in printToFile

Error message

Exception: in printToFile 

What it means

StringUtils.printToFile(File, String, boolean append, boolean printLn, String encoding) writes a message to a file through a PrintWriter. If opening or writing throws any Exception (missing directory, permissions, disk full, bad encoding), the method does not propagate it; it logs 'Exception: in printToFile <path>' via the logging framework and returns normally. The write silently fails from the caller's perspective.

Solutions

1. Ensure the parent directory exists before calling: file.getParentFile().mkdirs()
2. Check write permissions on the target path and that the disk is not full
3. Validate the encoding string (e.g. 'UTF-8')
4. Check the application log for the logged exception to identify the exact IOException
5. Switch to a writer API that throws (Files.write) if you need hard failure

Example fix

// before
StringUtils.printToFile(out, text, false, true, "UTF-8");
// after
File out = new File(path);
if (out.getParentFile() != null) out.getParentFile().mkdirs();
Files.write(out.toPath(), text.getBytes(StandardCharsets.UTF_8));

static void assertWritable(File f) throws java.io.IOException {
    File parent = f.getParentFile();
    if (parent != null && !parent.isDirectory() && !parent.mkdirs())
        throw new java.io.IOException("Cannot create dir: " + parent);
    if (f.exists() && !f.canWrite()) throw new java.io.IOException("Not writable: " + f);
}

try {
    StringUtils.printToFile(out, text, false, true, "UTF-8");
} catch (Exception e) { /* method swallows; verify instead */ }
if (!out.exists()) throw new java.io.IOException("printToFile failed silently for " + out);

When it happens

Trigger: Calling StringUtils.printToFile with a File whose parent directory does not exist, without write permission, on a read-only or full filesystem, or with an invalid charset name for the encoding argument.

Common situations: Writing output to a path with a typo or missing output directory; running as a user without write access; disk quota exceeded; wrong encoding string like 'utf_8'.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• Exception: in printToFileLn
• Error creating data exporter
• Serializing classifier to
• Error opening output file
• RuntimeIOException wrapping IOException from write

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/de59638050014a21. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/util/StringUtils.java:1205

  public static void printToFile(File file, String message, boolean append,
                                 boolean printLn, String encoding) {
    PrintWriter pw = null;
    try {
      Writer fw;
      if (encoding != null) {
        fw = new OutputStreamWriter(new FileOutputStream(file, append),
                                         encoding);
      } else {
        fw = new FileWriter(file, append);
      }
      pw = new PrintWriter(fw);
      if (printLn) {
        pw.println(message);
      } else {
        pw.print(message);
      }
    } catch (Exception e) {
      log.warn("Exception: in printToFile " + file.getAbsolutePath());
      log.warn(e);
    } finally {
      if (pw != null) {
        pw.flush();
        pw.close();
      }
    }
  }


  /**
   * Prints to a file.  If the file already exists, appends if
   * {@code append=true}, and overwrites if {@code append=false}.
   */
  public static void printToFileLn(File file, String message, boolean append) {
    PrintWriter pw = null;
    try {
      Writer fw = new FileWriter(file, append);

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