SiLeBAT/FSK-Lab

    FileUtils.writeStringToFile(rPackagesFile, packageInfoList, "UTF-8");

Close

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

        Files.walk(settingFolder.toPath()).sorted(Comparator.reverseOrder()).map(Path::toFile)

Close

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

  public void saveCurrentValue(NodeSettingsWO content) {}

Close

There are several reasons for a method not to have a method body:

• It is an unintentional omission, and should be fixed to prevent an unexpected behavior in production.
• It is not yet, or never will be, supported. In this case an UnsupportedOperationException should be thrown.
• The method is an intentionally-blank override. In this case a nested comment should explain the reason for the blank override.

Noncompliant Code Example

public void doSomething() {
}

public void doSomethingElse() {
}

Compliant Solution

@Override
public void doSomething() {
  // Do nothing because of X and Y.
}

@Override
public void doSomethingElse() {
  throw new UnsupportedOperationException();
}

Exceptions

Default (no-argument) constructors are ignored when there are other constructors in the class, as are empty methods in abstract classes.

public abstract class Animal {
  void speak() {  // default implementation ignored
  }
}

    String[] output = controller.execute(script.replaceAll("<-", "="));

Close

The underlying implementation of String::replaceAll calls the java.util.regex.Pattern.compile() method each time it is called even if the first argument is not a regular expression. This has a significant performance cost and therefore should be used with care.

When String::replaceAll is used, the first argument should be a real regular expression. If it’s not the case, String::replace does exactly the same thing as String::replaceAll without the performance drawback of the regex.

This rule raises an issue for each String::replaceAll used with a String as first parameter which doesn’t contains special regex character or pattern.

Noncompliant Code Example

String init = "Bob is a Bird... Bob is a Plane... Bob is Superman!";
String changed = init.replaceAll("Bob is", "It's"); // Noncompliant
changed = changed.replaceAll("\\.\\.\\.", ";"); // Noncompliant

Compliant Solution

String init = "Bob is a Bird... Bob is a Plane... Bob is Superman!";
String changed = init.replace("Bob is", "It's");
changed = changed.replace("...", ";");

Or, with a regex:

String init = "Bob is a Bird... Bob is a Plane... Bob is Superman!";
String changed = init.replaceAll("\\w*\\sis", "It's");
changed = changed.replaceAll("\\.{3}", ";");

See

• {rule:java:S4248} - Regex patterns should not be created needlessly

                final ObjectOutputStream oos = new ObjectOutputStream(out);

Close

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

                    final ObjectInputStream ois = new ObjectInputStream(in);

Close

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

    if (isNotNull("Variable", variableName) && isNotNull("Model ID", modelId)) {

Close

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

  private static FskPortObject readFskPortObject(CombineArchive archive, List<String> ListOfPaths,

Close

Cognitive Complexity is a measure of how hard the control flow of a method is to understand. Methods with high Cognitive Complexity will be difficult to maintain.

See

• Cognitive Complexity

    otherModel("Other Empirical models"),

Close

Shared coding conventions allow teams to collaborate efficiently. This rule checks that all constant names match a provided regular expression.

Noncompliant Code Example

With the default regular expression ^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$:

public class MyClass {
  public static final int first = 1;
}

public enum MyEnum {
  first;
}

Compliant Solution

public class MyClass {
  public static final int FIRST = 1;
}

public enum MyEnum {
  FIRST;
}

  private EnvironmentManager environment;

Close

Looking at the set of methods in a class, including superclass methods, and finding two methods or fields that differ only by capitalization is confusing to users of the class. It is similarly confusing to have a method and a field which differ only in capitalization or a method and a field with exactly the same name and visibility.

In the case of methods, it may have been a mistake on the part of the original developer, who intended to override a superclass method, but instead added a new method with nearly the same name.

Otherwise, this situation simply indicates poor naming. Method names should be action-oriented, and thus contain a verb, which is unlikely in the case where both a method and a member have the same name (with or without capitalization differences). However, renaming a public method could be disruptive to callers. Therefore renaming the member is the recommended action.

Noncompliant Code Example

public class Car{

  public DriveTrain drive;

  public void tearDown(){...}

  public void drive() {...}  // Noncompliant; duplicates field name
}

public class MyCar extends Car{
  public void teardown(){...}  // Noncompliant; not an override. It it really what's intended?

  public void drivefast(){...}

  public void driveFast(){...} //Huh?
}

Compliant Solution

public class Car{

  private DriveTrain drive;

  public void tearDown(){...}

  public void drive() {...}  // field visibility reduced
}

public class MyCar extends Car{
  @Override
  public void tearDown(){...}

  public void drivefast(){...}

  public void driveReallyFast(){...}

}

            psPossibleModelName = conn.prepareStatement(q);

Close

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

            PreparedStatement ps = conn.prepareStatement("INSERT INTO \"Messwerte\" (\"" + REL_CONDITION + "\", \"" + ATT_TIME + "\", \"ZeitEinheit\", \"" + ATT_LOG10N
                    + "\", \"Konz_Einheit\" )VALUES(?, ?, ?, ?, ?)");

Close

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

                psInsertDouble = conn.prepareStatement("INSERT INTO \"DoubleKennzahlen\" (\"" + ATT_VALUE + "\", \"" + ATT_VALUETYPE + "\" )VALUES(?, 1)",
                        Statement.RETURN_GENERATED_KEYS);

Close

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

            psQueryAgentId = conn.prepareStatement("SELECT \"ID\" FROM \"" + REL_AGENT + "\" WHERE \"" + ATT_AGENTNAME + "\" LIKE ? OR \"" + ATT_NAMESHORT + "\" LIKE ?");

Close

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

            PreparedStatement ps = conn.prepareStatement("SELECT \"ID\" FROM \"" + REL_MATRIX + "\" WHERE \"" + ATT_MATRIXNAME + "\" LIKE ?");

Close

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

                ps = conn.prepareStatement("UPDATE \"Versuchsbedingungen\" SET \"" + ATT_TEMPERATURE + "\"=?, \"" + ATT_PH + "\"=?, \"" + ATT_AW + "\"=?, \"" + ATT_AGENTID
                        + "\"=?, \"AgensDetail\"=?, \"" + ATT_MATRIXID + "\"=?, \"MatrixDetail\"=?, \"b_f_details_CB\"=?, \"Kommentar\"=?, \"Guetescore\"=?, \"Geprueft\"=?, \"Referenz\"=? WHERE \"ID\"=?");

Close

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

            + "        \"display in GUI as\" AS \"DepUnit\"\n" + "    FROM \"ModellkatalogParameter\"\n"

Close

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

            MiscXml mx = new MiscXml(rs.getInt("SonstigesID"), rs.getString("Parameter"), rs.getString("Beschreibung"), rs.getDouble("Wert"), null, rs.getString("Einheit"));

Close

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

                "Versuchsbedingungen_Sonstiges", "SonstigeParameter", "DoubleKennzahlen", "Messwerte", "Versuchsbedingungen" });

Close

Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

With the default threshold of 3:

public void run() {
  prepare("action1");                              // Noncompliant - "action1" is duplicated 3 times
  execute("action1");
  release("action1");
}

@SuppressWarning("all")                            // Compliant - annotations are excluded
private void method1() { /* ... */ }
@SuppressWarning("all")
private void method2() { /* ... */ }

public String method3(String a) {
  System.out.println("'" + a + "'");               // Compliant - literal "'" has less than 5 characters and is excluded
  return "";                                       // Compliant - literal "" has less than 5 characters and is excluded
}

Compliant Solution

private static final String ACTION_1 = "action1";  // Compliant

public void run() {
  prepare(ACTION_1);                               // Compliant
  execute(ACTION_1);
  release(ACTION_1);
}

Exceptions

To prevent generating some false-positives, literals having less than 5 characters are excluded.

    private static final String querySei2 = "SELECT *\n" + "\n" + "FROM(\n" + "\n" + queryPei2 + "\n" + ")\"PeiView\"\n" + "\n" + "    JOIN \"Sekundaermodelle_Primaermodelle\"\n"

Close

Shared coding conventions allow teams to collaborate efficiently. This rule checks that all constant names match a provided regular expression.

Noncompliant Code Example

With the default regular expression ^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$:

public class MyClass {
  public static final int first = 1;
}

public enum MyEnum {
  first;
}

Compliant Solution

public class MyClass {
  public static final int FIRST = 1;
}

public enum MyEnum {
  FIRST;
}