alkal-io/kalium

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Because printf-style format strings are interpreted at runtime, rather than validated by the compiler, they can contain errors that result in the wrong strings being created. This rule statically validates the correlation of printf-style format strings to their arguments when calling the format(...) methods of java.util.Formatter, java.lang.String, java.io.PrintStream, MessageFormat, and java.io.PrintWriter classes and the printf(...) methods of java.io.PrintStream or java.io.PrintWriter classes.

Noncompliant Code Example

String.format("First {0} and then {1}", "foo", "bar");  //Noncompliant. Looks like there is a confusion with the use of {{java.text.MessageFormat}}, parameters "foo" and "bar" will be simply ignored here
String.format("Display %3$d and then %d", 1, 2, 3);   //Noncompliant; the second argument '2' is unused
String.format("Too many arguments %d and %d", 1, 2, 3);  //Noncompliant; the third argument '3' is unused
String.format("First Line\n");   //Noncompliant; %n should be used in place of \n to produce the platform-specific line separator
String.format("Is myObject null ? %b", myObject);   //Noncompliant; when a non-boolean argument is formatted with %b, it prints true for any nonnull value, and false for null. Even if intended, this is misleading. It's better to directly inject the boolean value (myObject == null in this case)
String.format("value is " + value); // Noncompliant
String s = String.format("string without arguments"); // Noncompliant

MessageFormat.format("Result '{0}'.", value); // Noncompliant; String contains no format specifiers. (quote are discarding format specifiers)
MessageFormat.format("Result {0}.", value, value);  // Noncompliant; 2nd argument is not used
MessageFormat.format("Result {0}.", myObject.toString()); // Noncompliant; no need to call toString() on objects

java.util.Logger logger;
logger.log(java.util.logging.Level.SEVERE, "Result {0}.", myObject.toString()); // Noncompliant; no need to call toString() on objects
logger.log(java.util.logging.Level.SEVERE, "Result.", new Exception()); // compliant, parameter is an exception
logger.log(java.util.logging.Level.SEVERE, "Result '{0}'", 14); // Noncompliant - String contains no format specifiers.
logger.log(java.util.logging.Level.SEVERE, "Result " + param, exception); // Noncompliant; Lambda should be used to differ string concatenation.

org.slf4j.Logger slf4jLog;
org.slf4j.Marker marker;

slf4jLog.debug(marker, "message {}");
slf4jLog.debug(marker, "message", 1); // Noncompliant - String contains no format specifiers.

org.apache.logging.log4j.Logger log4jLog;
log4jLog.debug("message", 1); // Noncompliant - String contains no format specifiers.

Compliant Solution

String.format("First %s and then %s", "foo", "bar");
String.format("Display %2$d and then %d", 1, 3);
String.format("Too many arguments %d %d", 1, 2);
String.format("First Line%n");
String.format("Is myObject null ? %b", myObject == null);
String.format("value is %d", value);
String s = "string without arguments";

MessageFormat.format("Result {0}.", value);
MessageFormat.format("Result '{0}'  =  {0}", value);
MessageFormat.format("Result {0}.", myObject);

java.util.Logger logger;
logger.log(java.util.logging.Level.SEVERE, "Result {0}.", myObject);
logger.log(java.util.logging.Level.SEVERE, "Result {0}'", 14);
logger.log(java.util.logging.Level.SEVERE, exception, () -> "Result " + param);

org.slf4j.Logger slf4jLog;
org.slf4j.Marker marker;

slf4jLog.debug(marker, "message {}");
slf4jLog.debug(marker, "message {}", 1);

org.apache.logging.log4j.Logger log4jLog;
log4jLog.debug("message {}", 1);

See

• CERT, FIO47-C. - Use valid format strings

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Because printf-style format strings are interpreted at runtime, rather than validated by the compiler, they can contain errors that result in the wrong strings being created. This rule statically validates the correlation of printf-style format strings to their arguments when calling the format(...) methods of java.util.Formatter, java.lang.String, java.io.PrintStream, MessageFormat, and java.io.PrintWriter classes and the printf(...) methods of java.io.PrintStream or java.io.PrintWriter classes.

Noncompliant Code Example

String.format("First {0} and then {1}", "foo", "bar");  //Noncompliant. Looks like there is a confusion with the use of {{java.text.MessageFormat}}, parameters "foo" and "bar" will be simply ignored here
String.format("Display %3$d and then %d", 1, 2, 3);   //Noncompliant; the second argument '2' is unused
String.format("Too many arguments %d and %d", 1, 2, 3);  //Noncompliant; the third argument '3' is unused
String.format("First Line\n");   //Noncompliant; %n should be used in place of \n to produce the platform-specific line separator
String.format("Is myObject null ? %b", myObject);   //Noncompliant; when a non-boolean argument is formatted with %b, it prints true for any nonnull value, and false for null. Even if intended, this is misleading. It's better to directly inject the boolean value (myObject == null in this case)
String.format("value is " + value); // Noncompliant
String s = String.format("string without arguments"); // Noncompliant

MessageFormat.format("Result '{0}'.", value); // Noncompliant; String contains no format specifiers. (quote are discarding format specifiers)
MessageFormat.format("Result {0}.", value, value);  // Noncompliant; 2nd argument is not used
MessageFormat.format("Result {0}.", myObject.toString()); // Noncompliant; no need to call toString() on objects

java.util.Logger logger;
logger.log(java.util.logging.Level.SEVERE, "Result {0}.", myObject.toString()); // Noncompliant; no need to call toString() on objects
logger.log(java.util.logging.Level.SEVERE, "Result.", new Exception()); // compliant, parameter is an exception
logger.log(java.util.logging.Level.SEVERE, "Result '{0}'", 14); // Noncompliant - String contains no format specifiers.
logger.log(java.util.logging.Level.SEVERE, "Result " + param, exception); // Noncompliant; Lambda should be used to differ string concatenation.

org.slf4j.Logger slf4jLog;
org.slf4j.Marker marker;

slf4jLog.debug(marker, "message {}");
slf4jLog.debug(marker, "message", 1); // Noncompliant - String contains no format specifiers.

org.apache.logging.log4j.Logger log4jLog;
log4jLog.debug("message", 1); // Noncompliant - String contains no format specifiers.

Compliant Solution

String.format("First %s and then %s", "foo", "bar");
String.format("Display %2$d and then %d", 1, 3);
String.format("Too many arguments %d %d", 1, 2);
String.format("First Line%n");
String.format("Is myObject null ? %b", myObject == null);
String.format("value is %d", value);
String s = "string without arguments";

MessageFormat.format("Result {0}.", value);
MessageFormat.format("Result '{0}'  =  {0}", value);
MessageFormat.format("Result {0}.", myObject);

java.util.Logger logger;
logger.log(java.util.logging.Level.SEVERE, "Result {0}.", myObject);
logger.log(java.util.logging.Level.SEVERE, "Result {0}'", 14);
logger.log(java.util.logging.Level.SEVERE, exception, () -> "Result " + param);

org.slf4j.Logger slf4jLog;
org.slf4j.Marker marker;

slf4jLog.debug(marker, "message {}");
slf4jLog.debug(marker, "message {}", 1);

org.apache.logging.log4j.Logger log4jLog;
log4jLog.debug("message {}", 1);

See

• CERT, FIO47-C. - Use valid format strings

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Generic types shouldn't be used raw (without type parameters) in variable declarations or return values. Doing so bypasses generic type checking, and defers the catch of unsafe code to runtime.

Noncompliant Code Example

List myList; // Noncompliant
Set mySet; // Noncompliant

Compliant Solution

List<String> myList;
Set<? extends Number> mySet;

Passing message arguments that require further evaluation into a Guava com.google.common.base.Preconditions check can result in a performance penalty. That's because whether or not they're needed, each argument must be resolved before the method is actually called.

Similarly, passing concatenated strings into a logging method can also incur a needless performance hit because the concatenation will be performed every time the method is called, whether or not the log level is low enough to show the message.

Instead, you should structure your code to pass static or pre-computed values into Preconditions conditions check and logging calls.

Specifically, the built-in string formatting should be used instead of string concatenation, and if the message is the result of a method call, then Preconditions should be skipped altogether, and the relevant exception should be conditionally thrown instead.

Noncompliant Code Example

logger.log(Level.DEBUG, "Something went wrong: " + message);  // Noncompliant; string concatenation performed even when log level too high to show DEBUG messages

logger.fine("An exception occurred with message: " + message); // Noncompliant

LOG.error("Unable to open file " + csvPath, e);  // Noncompliant

Preconditions.checkState(a > 0, "Arg must be positive, but got " + a);  // Noncompliant. String concatenation performed even when a > 0

Preconditions.checkState(condition, formatMessage());  // Noncompliant. formatMessage() invoked regardless of condition

Preconditions.checkState(condition, "message: %s", formatMessage());  // Noncompliant

Compliant Solution

logger.log(Level.SEVERE, "Something went wrong: {0} ", message);  // String formatting only applied if needed

logger.fine("An exception occurred with message: {}", message);  // SLF4J, Log4j

logger.log(Level.SEVERE, () -> "Something went wrong: " + message); // since Java 8, we can use Supplier , which will be evaluated lazily

LOG.error("Unable to open file {0}", csvPath, e);

if (LOG.isDebugEnabled() {
  LOG.debug("Unable to open file " + csvPath, e);  // this is compliant, because it will not evaluate if log level is above debug.
}

Preconditions.checkState(arg > 0, "Arg must be positive, but got %d", a);  // String formatting only applied if needed

if (!condition) {
  throw new IllegalStateException(formatMessage());  // formatMessage() only invoked conditionally
}

if (!condition) {
  throw new IllegalStateException("message: " + formatMessage());
}

Exceptions

catch blocks are ignored, because the performance penalty is unimportant on exceptional paths (catch block should not be a part of standard program flow). Getters are ignored as well as methods called on annotations which can be considered as getters. This rule accounts for explicit test-level testing with SLF4J methods isXXXEnabled and ignores the bodies of such if statements.

Passing message arguments that require further evaluation into a Guava com.google.common.base.Preconditions check can result in a performance penalty. That's because whether or not they're needed, each argument must be resolved before the method is actually called.

Similarly, passing concatenated strings into a logging method can also incur a needless performance hit because the concatenation will be performed every time the method is called, whether or not the log level is low enough to show the message.

Instead, you should structure your code to pass static or pre-computed values into Preconditions conditions check and logging calls.

Specifically, the built-in string formatting should be used instead of string concatenation, and if the message is the result of a method call, then Preconditions should be skipped altogether, and the relevant exception should be conditionally thrown instead.

Noncompliant Code Example

logger.log(Level.DEBUG, "Something went wrong: " + message);  // Noncompliant; string concatenation performed even when log level too high to show DEBUG messages

logger.fine("An exception occurred with message: " + message); // Noncompliant

LOG.error("Unable to open file " + csvPath, e);  // Noncompliant

Preconditions.checkState(a > 0, "Arg must be positive, but got " + a);  // Noncompliant. String concatenation performed even when a > 0

Preconditions.checkState(condition, formatMessage());  // Noncompliant. formatMessage() invoked regardless of condition

Preconditions.checkState(condition, "message: %s", formatMessage());  // Noncompliant

Compliant Solution

logger.log(Level.SEVERE, "Something went wrong: {0} ", message);  // String formatting only applied if needed

logger.fine("An exception occurred with message: {}", message);  // SLF4J, Log4j

logger.log(Level.SEVERE, () -> "Something went wrong: " + message); // since Java 8, we can use Supplier , which will be evaluated lazily

LOG.error("Unable to open file {0}", csvPath, e);

if (LOG.isDebugEnabled() {
  LOG.debug("Unable to open file " + csvPath, e);  // this is compliant, because it will not evaluate if log level is above debug.
}

Preconditions.checkState(arg > 0, "Arg must be positive, but got %d", a);  // String formatting only applied if needed

if (!condition) {
  throw new IllegalStateException(formatMessage());  // formatMessage() only invoked conditionally
}

if (!condition) {
  throw new IllegalStateException("message: " + formatMessage());
}

Exceptions

catch blocks are ignored, because the performance penalty is unimportant on exceptional paths (catch block should not be a part of standard program flow). Getters are ignored as well as methods called on annotations which can be considered as getters. This rule accounts for explicit test-level testing with SLF4J methods isXXXEnabled and ignores the bodies of such if statements.

Passing message arguments that require further evaluation into a Guava com.google.common.base.Preconditions check can result in a performance penalty. That's because whether or not they're needed, each argument must be resolved before the method is actually called.

Similarly, passing concatenated strings into a logging method can also incur a needless performance hit because the concatenation will be performed every time the method is called, whether or not the log level is low enough to show the message.

Instead, you should structure your code to pass static or pre-computed values into Preconditions conditions check and logging calls.

Specifically, the built-in string formatting should be used instead of string concatenation, and if the message is the result of a method call, then Preconditions should be skipped altogether, and the relevant exception should be conditionally thrown instead.

Noncompliant Code Example

logger.log(Level.DEBUG, "Something went wrong: " + message);  // Noncompliant; string concatenation performed even when log level too high to show DEBUG messages

logger.fine("An exception occurred with message: " + message); // Noncompliant

LOG.error("Unable to open file " + csvPath, e);  // Noncompliant

Preconditions.checkState(a > 0, "Arg must be positive, but got " + a);  // Noncompliant. String concatenation performed even when a > 0

Preconditions.checkState(condition, formatMessage());  // Noncompliant. formatMessage() invoked regardless of condition

Preconditions.checkState(condition, "message: %s", formatMessage());  // Noncompliant

Compliant Solution

logger.log(Level.SEVERE, "Something went wrong: {0} ", message);  // String formatting only applied if needed

logger.fine("An exception occurred with message: {}", message);  // SLF4J, Log4j

logger.log(Level.SEVERE, () -> "Something went wrong: " + message); // since Java 8, we can use Supplier , which will be evaluated lazily

LOG.error("Unable to open file {0}", csvPath, e);

if (LOG.isDebugEnabled() {
  LOG.debug("Unable to open file " + csvPath, e);  // this is compliant, because it will not evaluate if log level is above debug.
}

Preconditions.checkState(arg > 0, "Arg must be positive, but got %d", a);  // String formatting only applied if needed

if (!condition) {
  throw new IllegalStateException(formatMessage());  // formatMessage() only invoked conditionally
}

if (!condition) {
  throw new IllegalStateException("message: " + formatMessage());
}

Exceptions

catch blocks are ignored, because the performance penalty is unimportant on exceptional paths (catch block should not be a part of standard program flow). Getters are ignored as well as methods called on annotations which can be considered as getters. This rule accounts for explicit test-level testing with SLF4J methods isXXXEnabled and ignores the bodies of such if statements.

Passing message arguments that require further evaluation into a Guava com.google.common.base.Preconditions check can result in a performance penalty. That's because whether or not they're needed, each argument must be resolved before the method is actually called.

Similarly, passing concatenated strings into a logging method can also incur a needless performance hit because the concatenation will be performed every time the method is called, whether or not the log level is low enough to show the message.

Instead, you should structure your code to pass static or pre-computed values into Preconditions conditions check and logging calls.

Specifically, the built-in string formatting should be used instead of string concatenation, and if the message is the result of a method call, then Preconditions should be skipped altogether, and the relevant exception should be conditionally thrown instead.

Noncompliant Code Example

logger.log(Level.DEBUG, "Something went wrong: " + message);  // Noncompliant; string concatenation performed even when log level too high to show DEBUG messages

logger.fine("An exception occurred with message: " + message); // Noncompliant

LOG.error("Unable to open file " + csvPath, e);  // Noncompliant

Preconditions.checkState(a > 0, "Arg must be positive, but got " + a);  // Noncompliant. String concatenation performed even when a > 0

Preconditions.checkState(condition, formatMessage());  // Noncompliant. formatMessage() invoked regardless of condition

Preconditions.checkState(condition, "message: %s", formatMessage());  // Noncompliant

Compliant Solution

logger.log(Level.SEVERE, "Something went wrong: {0} ", message);  // String formatting only applied if needed

logger.fine("An exception occurred with message: {}", message);  // SLF4J, Log4j

logger.log(Level.SEVERE, () -> "Something went wrong: " + message); // since Java 8, we can use Supplier , which will be evaluated lazily

LOG.error("Unable to open file {0}", csvPath, e);

if (LOG.isDebugEnabled() {
  LOG.debug("Unable to open file " + csvPath, e);  // this is compliant, because it will not evaluate if log level is above debug.
}

Preconditions.checkState(arg > 0, "Arg must be positive, but got %d", a);  // String formatting only applied if needed

if (!condition) {
  throw new IllegalStateException(formatMessage());  // formatMessage() only invoked conditionally
}

if (!condition) {
  throw new IllegalStateException("message: " + formatMessage());
}

Exceptions

catch blocks are ignored, because the performance penalty is unimportant on exceptional paths (catch block should not be a part of standard program flow). Getters are ignored as well as methods called on annotations which can be considered as getters. This rule accounts for explicit test-level testing with SLF4J methods isXXXEnabled and ignores the bodies of such if statements.

Checks that the groups of import declarations appear in the order specifiedby the user. If there is an import but its group is not specified in theconfiguration such an import should be placed at the end of the import list.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks thatJavadoc summary sentence does not contain phrases that are not recommended to use.Summaries that contain only the {@inheritDoc} tag are skipped. Check alsoviolate Javadoc that does not contain first sentence.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks that there are no import statements that use the * notation.

Rationale: Importing all classes from a package or staticmembers from a class leads to tight coupling between packagesor classes and might lead to problems when a new version of alibrary introduces name clashes.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks for long lines.

Rationale: Long lines are hard to read in printouts or if developershave limited screen space for the source code, e.g. if the IDEdisplays additional information like project tree, class hierarchy,etc.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks that method parameter names conform to a specified pattern.By using accessModifiers property it is possibleto specify different formats for methods at different visibility levels.

To validate catch parameters please useCatchParameterName.

To validate lambda parameters please useLambdaParameterName.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks the policy on how to wrap lines on operators.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks that method parameter names conform to a specified pattern.By using accessModifiers property it is possibleto specify different formats for methods at different visibility levels.

To validate catch parameters please useCatchParameterName.

To validate lambda parameters please useLambdaParameterName.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks for long lines.

Rationale: Long lines are hard to read in printouts or if developershave limited screen space for the source code, e.g. if the IDEdisplays additional information like project tree, class hierarchy,etc.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks that method parameter names conform to a specified pattern.By using accessModifiers property it is possibleto specify different formats for methods at different visibility levels.

To validate catch parameters please useCatchParameterName.

To validate lambda parameters please useLambdaParameterName.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks the policy on how to wrap lines on operators.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks for braces around code blocks.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks for long lines.

Rationale: Long lines are hard to read in printouts or if developershave limited screen space for the source code, e.g. if the IDEdisplays additional information like project tree, class hierarchy,etc.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks the indentation of the continuation lines in block tags.That is whether thecontinued description of at clauses should be indented or not. If the text is not properlyindented it throws a violation. A continuation line is when the description starts/spanspast the line with the tag. Default indentation required is at least 4, but this can bechanged with the help of properties below.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks for long lines.

Rationale: Long lines are hard to read in printouts or if developershave limited screen space for the source code, e.g. if the IDEdisplays additional information like project tree, class hierarchy,etc.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks that method parameter names conform to a specified pattern.By using accessModifiers property it is possibleto specify different formats for methods at different visibility levels.

To validate catch parameters please useCatchParameterName.

To validate lambda parameters please useLambdaParameterName.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.

Checks for long lines.

Rationale: Long lines are hard to read in printouts or if developershave limited screen space for the source code, e.g. if the IDEdisplays additional information like project tree, class hierarchy,etc.

This documentation is written and maintained by the Checkstyle community and is covered under the same license as the Checkstyle project.