Showing 392 of 393 total issues
Remove this expression which always evaluates to "true" Open
if (cache != null && mCacheEnabled && cache.createdAt.isAfter(DateTime.now().minusSeconds(60))) {
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If a boolean expression doesn't change the evaluation of the condition, then it is entirely unnecessary, and can be removed. If it is gratuitous because it does not match the programmer's intent, then it's a bug and the expression should be fixed.
Noncompliant Code Example
a = true; if (a) { // Noncompliant doSomething(); } if (b && a) { // Noncompliant; "a" is always "true" doSomething(); } if (c || !a) { // Noncompliant; "!a" is always "false" doSomething(); }
Compliant Solution
a = true; if (foo(a)) { doSomething(); } if (b) { doSomething(); } if (c) { doSomething(); }
See
- MITRE, CWE-571 - Expression is Always True
- MITRE, CWE-570 - Expression is Always False
Define a constant instead of duplicating this literal "platform" 3 times. Open
platform = json.getString("platform");
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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.
This block of commented-out lines of code should be removed. Open
// Log::info("[{$connection->getId()}] Transferring not possible: No transfers exist");
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Programmers should not comment out code as it bloats programs and reduces readability.
Unused code should be deleted and can be retrieved from source control history if required.
Define a constant instead of duplicating this literal "station" 3 times. Open
i.putExtra("station", semanticStationId); // shortcut intents should not contain application specific classes - only pass the station ID
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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.
Define a constant instead of duplicating this literal "result" 3 times. Open
outState.putSerializable("result", mCurrentTrain);
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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.
Either re-interrupt this method or rethrow the "InterruptedException" that can be caught here. Open
} catch (InterruptedException e) {
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InterruptedExceptions
should never be ignored in the code, and simply logging the exception counts in this case as "ignoring". The
throwing of the InterruptedException
clears the interrupted state of the Thread, so if the exception is not handled properly the fact
that the thread was interrupted will be lost. Instead, InterruptedExceptions
should either be rethrown - immediately or after cleaning up
the method's state - or the thread should be re-interrupted by calling Thread.interrupt()
even if this is supposed to be a
single-threaded application. Any other course of action risks delaying thread shutdown and loses the information that the thread was interrupted -
probably without finishing its task.
Similarly, the ThreadDeath
exception should also be propagated. According to its JavaDoc:
If
ThreadDeath
is caught by a method, it is important that it be rethrown so that the thread actually dies.
Noncompliant Code Example
public void run () { try { while (true) { // do stuff } }catch (InterruptedException e) { // Noncompliant; logging is not enough LOGGER.log(Level.WARN, "Interrupted!", e); } }
Compliant Solution
public void run () { try { while (true) { // do stuff } }catch (InterruptedException e) { LOGGER.log(Level.WARN, "Interrupted!", e); // Restore interrupted state... Thread.currentThread().interrupt(); } }
See
- MITRE, CWE-391 - Unchecked Error Condition
- Dealing with InterruptedException
Constructor has 21 parameters, which is greater than 7 authorized. Open
public StopLocationFacilitiesImpl(LocalTime[][] openingHours, String street, String zip, String city, boolean ticketVendingMachines,
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A long parameter list can indicate that a new structure should be created to wrap the numerous parameters or that the function is doing too many things.
Noncompliant Code Example
With a maximum number of 4 parameters:
public void doSomething(int param1, int param2, int param3, String param4, long param5) { ... }
Compliant Solution
public void doSomething(int param1, int param2, int param3, String param4) { ... }
Exceptions
Methods annotated with :
- Spring's
@RequestMapping
(and related shortcut annotations, like@GetRequest
) - JAX-RS API annotations (like
@javax.ws.rs.GET
) - Bean constructor injection with
@org.springframework.beans.factory.annotation.Autowired
- CDI constructor injection with
@javax.inject.Inject
-
@com.fasterxml.jackson.annotation.JsonCreator
may have a lot of parameters, encapsulation being possible. Such methods are therefore ignored.
Remove this unused "attachment" private field. Open
private final String attachment;
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If a private
field is declared but not used in the program, it can be considered dead code and should therefore be removed. This will
improve maintainability because developers will not wonder what the variable is used for.
Note that this rule does not take reflection into account, which means that issues will be raised on private
fields that are only
accessed using the reflection API.
Noncompliant Code Example
public class MyClass { private int foo = 42; public int compute(int a) { return a * 42; } }
Compliant Solution
public class MyClass { public int compute(int a) { return a * 42; } }
Exceptions
The Java serialization runtime associates with each serializable class a version number, called serialVersionUID
, which is used during
deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to
serialization.
A serializable class can declare its own serialVersionUID
explicitly by declaring a field named serialVersionUID
that
must be static, final, and of type long. By definition those serialVersionUID
fields should not be reported by this rule:
public class MyClass implements java.io.Serializable { private static final long serialVersionUID = 42L; }
Moreover, this rule doesn't raise any issue on annotated fields.
Provide the parametrized type for this generic. Open
private final Class callingClass;
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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;
Define a constant instead of duplicating this literal "vehicle" 3 times. Open
String headsign = parseHeadsign(json.getJSONObject("vehicle"));
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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.
This block of commented-out lines of code should be removed. Open
"vehicle": {
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Programmers should not comment out code as it bloats programs and reduces readability.
Unused code should be deleted and can be retrieved from source control history if required.
This block of commented-out lines of code should be removed. Open
// Log::info("[{$connection->getId()}] Remaining seated possible with arrival time $T2_stayOnTripArrivalTime and $T2_transfers transfers.");
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Programmers should not comment out code as it bloats programs and reduces readability.
Unused code should be deleted and can be retrieved from source control history if required.
This block of commented-out lines of code should be removed. Open
// Log::info("Train time!");
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Programmers should not comment out code as it bloats programs and reduces readability.
Unused code should be deleted and can be retrieved from source control history if required.
Remove this useless assignment to local variable "id". Open
int id = (int) db.insertWithOnConflict(TABLE, null, values, SQLiteDatabase.CONFLICT_REPLACE);
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A dead store happens when a local variable is assigned a value that is not read by any subsequent instruction. Calculating or retrieving a value only to then overwrite it or throw it away, could indicate a serious error in the code. Even if it's not an error, it is at best a waste of resources. Therefore all calculated values should be used.
Noncompliant Code Example
i = a + b; // Noncompliant; calculation result not used before value is overwritten i = compute();
Compliant Solution
i = a + b; i += compute();
Exceptions
This rule ignores initializations to -1, 0, 1, null
, true
, false
and ""
.
See
- MITRE, CWE-563 - Assignment to Variable without Use ('Unused Variable')
- CERT, MSC13-C. - Detect and remove unused values
- CERT, MSC56-J. - Detect and remove superfluous code and values
Refactor this method to reduce its Cognitive Complexity from 20 to the 15 allowed. Open
void getLinkedConnectionsByUrl(final String url, final TransportDataSuccessResponseListener<LinkedConnections> successListener, final TransportDataErrorResponseListener errorListener, final Object tag) {
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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
Remove this unused "GTFS_DROP_OFF_TYPE" private field. Open
private static final String GTFS_DROP_OFF_TYPE = "gtfs:dropOffType";
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If a private
field is declared but not used in the program, it can be considered dead code and should therefore be removed. This will
improve maintainability because developers will not wonder what the variable is used for.
Note that this rule does not take reflection into account, which means that issues will be raised on private
fields that are only
accessed using the reflection API.
Noncompliant Code Example
public class MyClass { private int foo = 42; public int compute(int a) { return a * 42; } }
Compliant Solution
public class MyClass { public int compute(int a) { return a * 42; } }
Exceptions
The Java serialization runtime associates with each serializable class a version number, called serialVersionUID
, which is used during
deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to
serialization.
A serializable class can declare its own serialVersionUID
explicitly by declaring a field named serialVersionUID
that
must be static, final, and of type long. By definition those serialVersionUID
fields should not be reported by this rule:
public class MyClass implements java.io.Serializable { private static final long serialVersionUID = 42L; }
Moreover, this rule doesn't raise any issue on annotated fields.
Constructor has 8 parameters, which is greater than 7 authorized. Open
public VehicleCompositionUnitImpl(int drawableResource, Integer publicFacingNumber, String publicTypeName, boolean hasToilet, boolean hasAirco, boolean canPassToNextUnit, int numberOfFirstClassSeats, int numberOfSecondClassSeats) {
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A long parameter list can indicate that a new structure should be created to wrap the numerous parameters or that the function is doing too many things.
Noncompliant Code Example
With a maximum number of 4 parameters:
public void doSomething(int param1, int param2, int param3, String param4, long param5) { ... }
Compliant Solution
public void doSomething(int param1, int param2, int param3, String param4) { ... }
Exceptions
Methods annotated with :
- Spring's
@RequestMapping
(and related shortcut annotations, like@GetRequest
) - JAX-RS API annotations (like
@javax.ws.rs.GET
) - Bean constructor injection with
@org.springframework.beans.factory.annotation.Autowired
- CDI constructor injection with
@javax.inject.Inject
-
@com.fasterxml.jackson.annotation.JsonCreator
may have a lot of parameters, encapsulation being possible. Such methods are therefore ignored.
Add the missing @deprecated Javadoc tag. Open
Transfer[] getTransfers();
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Deprecation should be marked with both the @Deprecated
annotation and @deprecated Javadoc tag. The annotation enables tools such as
IDEs to warn about referencing deprecated elements, and the tag can be used to explain when it was deprecated, why, and how references should be
refactored.
Further, Java 9 adds two additional arguments to the annotation:
-
since
allows you to describe when the deprecation took place -
forRemoval
, indicates whether the deprecated element will be removed at some future date
If your compile level is Java 9 or higher, you should be using one or both of these arguments.
Noncompliant Code Example
class MyClass { @Deprecated public void foo1() { } /** * @deprecated */ public void foo2() { // Noncompliant } }
Compliant Solution
class MyClass { /** * @deprecated (when, why, refactoring advice...) */ @Deprecated public void foo1() { } /** * Java >= 9 * @deprecated (when, why, refactoring advice...) */ @Deprecated(since="5.1") public void foo2() { } /** * Java >= 9 * @deprecated (when, why, refactoring advice...) */ @Deprecated(since="4.2", forRemoval=true) public void foo3() { } }
Exceptions
The members and methods of a deprecated class or interface are ignored by this rule. The classes and interfaces themselves are still subject to it.
/** * @deprecated (when, why, etc...) */ @Deprecated class Qix { public void foo() {} // Compliant; class is deprecated } /** * @deprecated (when, why, etc...) */ @Deprecated interface Plop { void bar(); }
This block of commented-out lines of code should be removed. Open
// current time as a default;
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Programmers should not comment out code as it bloats programs and reduces readability.
Unused code should be deleted and can be retrieved from source control history if required.
Define a constant instead of duplicating this literal " \"time\": \"1510835040\",
" 3 times. Open
" \"time\": \"1510835040\",\n" +
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- Exclude checks
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.