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Consequently, file operations can silently fail if the methods' return values are ignored. Java programs must check the return values of method that perform file I/O (this is a specific instance of rule EXP00-J. Do not ignore values returned by methods.)

Noncompliant Code Example (delete())

This noncompliant code example attempts to delete a specified file, but gives no indication of its success. The [API 2006] requires File.delete() to only throw a SecurityException if the program is not authorized to delete the file. No other exceptions are thrown; so the deletion can silently fail.

File file = /* initialize */
file.delete();

Compliant Solution

This compliant solution checks the return value of delete().

File file = new File(args[0]);
if (!file.delete()) {
  System.out.println("Deletion failed");
}

Compliant Solution (Java 1.7)

This compliant solution uses the Files.delete() method from Java 1.7 to delete the file.

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Risk Assessment

Failure to check the return values of methods that perform file I/O can result in unexpected behavior.

Automated Detection

TODO

Related Guidelines

Bibliography

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