Use try-with-resources or close this "!Unknown!" in a "finally" clause. Open
Files.walk(workflowContext.getCurrentLocation().toPath())
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- Exclude checks
Connections, streams, files, and other classes that implement the Closeable
interface or its super-interface,
AutoCloseable
, needs to be closed after use. Further, that close
call must be made in a finally
block otherwise
an exception could keep the call from being made. Preferably, when class implements AutoCloseable
, resource should be created using
"try-with-resources" pattern and will be closed automatically.
Failure to properly close resources will result in a resource leak which could bring first the application and then perhaps the box the application is on to their knees.
Noncompliant Code Example
private void readTheFile() throws IOException { Path path = Paths.get(this.fileName); BufferedReader reader = Files.newBufferedReader(path, this.charset); // ... reader.close(); // Noncompliant // ... Files.lines("input.txt").forEach(System.out::println); // Noncompliant: The stream needs to be closed } private void doSomething() { OutputStream stream = null; try { for (String property : propertyList) { stream = new FileOutputStream("myfile.txt"); // Noncompliant // ... } } catch (Exception e) { // ... } finally { stream.close(); // Multiple streams were opened. Only the last is closed. } }
Compliant Solution
private void readTheFile(String fileName) throws IOException { Path path = Paths.get(fileName); try (BufferedReader reader = Files.newBufferedReader(path, StandardCharsets.UTF_8)) { reader.readLine(); // ... } // .. try (Stream<String> input = Files.lines("input.txt")) { input.forEach(System.out::println); } } private void doSomething() { OutputStream stream = null; try { stream = new FileOutputStream("myfile.txt"); for (String property : propertyList) { // ... } } catch (Exception e) { // ... } finally { stream.close(); } }
Exceptions
Instances of the following classes are ignored by this rule because close
has no effect:
-
java.io.ByteArrayOutputStream
-
java.io.ByteArrayInputStream
-
java.io.CharArrayReader
-
java.io.CharArrayWriter
-
java.io.StringReader
-
java.io.StringWriter
Java 7 introduced the try-with-resources statement, which implicitly closes Closeables
. All resources opened in a try-with-resources
statement are ignored by this rule.
try (BufferedReader br = new BufferedReader(new FileReader(fileName))) { //... } catch ( ... ) { //... }
See
- MITRE, CWE-459 - Incomplete Cleanup
- MITRE, CWE-772 - Missing Release of Resource after Effective Lifetime
- CERT, FIO04-J. - Release resources when they are no longer needed
- CERT, FIO42-C. - Close files when they are no longer needed
- Try With Resources
Identical blocks of code found in 2 locations. Consider refactoring. Open
@Override
protected PortObjectSpec[] configure(PortObjectSpec[] inSpecs) throws InvalidSettingsException {
String warning = CheckUtils.checkSourceFile(filePath.getStringValue());
if (warning != null) {
setWarningMessage(warning);
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Duplicated Code
Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).
Tuning
This issue has a mass of 46.
We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.
The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.
If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.
See codeclimate-duplication
's documentation for more information about tuning the mass threshold in your .codeclimate.yml
.
Refactorings
- Extract Method
- Extract Class
- Form Template Method
- Introduce Null Object
- Pull Up Method
- Pull Up Field
- Substitute Algorithm
Further Reading
- Don't Repeat Yourself on the C2 Wiki
- Duplicated Code on SourceMaking
- Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76