Showing 392 of 393 total issues
Define a constant instead of duplicating this literal " \"name\": \"Brugge\"
" 3 times. Open
" \"name\": \"Brugge\"\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.
Define a constant instead of duplicating this literal " \"occupancy\": {
" 6 times. Open
" \"occupancy\": {\n" +
- Read upRead up
- 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.
Define and throw a dedicated exception instead of using a generic one. Open
public void liveboardParsingTest() throws Exception {
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- Exclude checks
Using such generic exceptions as Error
, RuntimeException
, Throwable
, and Exception
prevents
calling methods from handling true, system-generated exceptions differently than application-generated errors.
Noncompliant Code Example
public void foo(String bar) throws Throwable { // Noncompliant throw new RuntimeException("My Message"); // Noncompliant }
Compliant Solution
public void foo(String bar) { throw new MyOwnRuntimeException("My Message"); }
Exceptions
Generic exceptions in the signatures of overriding methods are ignored, because overriding method has to follow signature of the throw declaration in the superclass. The issue will be raised on superclass declaration of the method (or won't be raised at all if superclass is not part of the analysis).
@Override public void myMethod() throws Exception {...}
Generic exceptions are also ignored in the signatures of methods that make calls to methods that throw generic exceptions.
public void myOtherMethod throws Exception { doTheThing(); // this method throws Exception }
See
- MITRE, CWE-397 - Declaration of Throws for Generic Exception
- CERT, ERR07-J. - Do not throw RuntimeException, Exception, or Throwable
Define a constant instead of duplicating this literal " \"locationY\": \"51.056365\",
" 6 times. Open
" \"locationY\": \"51.056365\",\n" +
- Read upRead up
- 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.
Add the missing @deprecated Javadoc tag. Open
private static String getVehicleNumber(String vehicleId) {
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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(); }
Define a constant instead of duplicating this literal " \"left\": \"0\",
" 9 times. Open
" \"left\": \"0\",\n" +
- Read upRead up
- 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.
Define a constant instead of duplicating this literal " NUMERIC," 17 times. Open
StationFacilityColumns.COLUMN_TICKET_VENDING_MACHINE + " NUMERIC," +
- Read upRead up
- 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.
Define a constant instead of duplicating this literal " \"station\": \"Kiewit\",
" 6 times. Open
" \"station\": \"Kiewit\",\n" +
- Read upRead up
- 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.
Remove this useless assignment to local variable "jsObjRequest". Open
JsonObjectRequest jsObjRequest = new JsonObjectRequest
(Request.Method.GET, url, null, successListener, errorListener) {
@Override
public Map<String, String> getHeaders() {
Map<String, String> headers = new HashMap<>();
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- Exclude checks
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
Add a private constructor to hide the implicit public one. Open
public static final class StationFacilityColumns implements BaseColumns {
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Utility classes, which are collections of static
members, are not meant to be instantiated. Even abstract utility classes, which can
be extended, should not have public constructors.
Java adds an implicit public constructor to every class which does not define at least one explicitly. Hence, at least one non-public constructor should be defined.
Noncompliant Code Example
class StringUtils { // Noncompliant public static String concatenate(String s1, String s2) { return s1 + s2; } }
Compliant Solution
class StringUtils { // Compliant private StringUtils() { throw new IllegalStateException("Utility class"); } public static String concatenate(String s1, String s2) { return s1 + s2; } }
Exceptions
When class contains public static void main(String[] args)
method it is not considered as utility class and will be ignored by this
rule.
Add a private constructor to hide the implicit public one. Open
public class IrailStationFacilitiesDataContract {
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Utility classes, which are collections of static
members, are not meant to be instantiated. Even abstract utility classes, which can
be extended, should not have public constructors.
Java adds an implicit public constructor to every class which does not define at least one explicitly. Hence, at least one non-public constructor should be defined.
Noncompliant Code Example
class StringUtils { // Noncompliant public static String concatenate(String s1, String s2) { return s1 + s2; } }
Compliant Solution
class StringUtils { // Compliant private StringUtils() { throw new IllegalStateException("Utility class"); } public static String concatenate(String s1, String s2) { return s1 + s2; } }
Exceptions
When class contains public static void main(String[] args)
method it is not considered as utility class and will be ignored by this
rule.
Define a constant instead of duplicating this literal "materialType" 3 times. Open
String parentType = jsonObject.getJSONObject("materialType").getString("parent_type").toUpperCase();
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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.
Add a default case to this switch. Open
switch (parentType) {
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The requirement for a final default
clause is defensive programming. The clause should either take appropriate action, or contain a
suitable comment as to why no action is taken.
Noncompliant Code Example
switch (param) { //missing default clause case 0: doSomething(); break; case 1: doSomethingElse(); break; } switch (param) { default: // default clause should be the last one error(); break; case 0: doSomething(); break; case 1: doSomethingElse(); break; }
Compliant Solution
switch (param) { case 0: doSomething(); break; case 1: doSomethingElse(); break; default: error(); break; }
Exceptions
If the switch
parameter is an Enum
and if all the constants of this enum are used in the case
statements,
then no default
clause is expected.
Example:
public enum Day { SUNDAY, MONDAY } ... switch(day) { case SUNDAY: doSomething(); break; case MONDAY: doSomethingElse(); break; }
See
- MITRE, CWE-478 - Missing Default Case in Switch Statement
- CERT, MSC01-C. - Strive for logical completeness
Define a constant instead of duplicating this literal "direction" 3 times. Open
departure.getJSONObject("direction").getString("name")
- Read upRead up
- 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.
Add a default case to this switch. Open
switch (subType) {
- Read upRead up
- Exclude checks
The requirement for a final default
clause is defensive programming. The clause should either take appropriate action, or contain a
suitable comment as to why no action is taken.
Noncompliant Code Example
switch (param) { //missing default clause case 0: doSomething(); break; case 1: doSomethingElse(); break; } switch (param) { default: // default clause should be the last one error(); break; case 0: doSomething(); break; case 1: doSomethingElse(); break; }
Compliant Solution
switch (param) { case 0: doSomething(); break; case 1: doSomethingElse(); break; default: error(); break; }
Exceptions
If the switch
parameter is an Enum
and if all the constants of this enum are used in the case
statements,
then no default
clause is expected.
Example:
public enum Day { SUNDAY, MONDAY } ... switch(day) { case SUNDAY: doSomething(); break; case MONDAY: doSomethingElse(); break; }
See
- MITRE, CWE-478 - Missing Default Case in Switch Statement
- CERT, MSC01-C. - Strive for logical completeness
End this switch case with an unconditional break, return or throw statement. Open
case "HLE21":
- Read upRead up
- Exclude checks
When the execution is not explicitly terminated at the end of a switch case, it continues to execute the statements of the following case. While this is sometimes intentional, it often is a mistake which leads to unexpected behavior.
Noncompliant Code Example
switch (myVariable) { case 1: foo(); break; case 2: // Both 'doSomething()' and 'doSomethingElse()' will be executed. Is it on purpose ? doSomething(); default: doSomethingElse(); break; }
Compliant Solution
switch (myVariable) { case 1: foo(); break; case 2: doSomething(); break; default: doSomethingElse(); break; }
Exceptions
This rule is relaxed in the following cases:
switch (myVariable) { case 0: // Empty case used to specify the same behavior for a group of cases. case 1: doSomething(); break; case 2: // Use of return statement return; case 3: // Use of throw statement throw new IllegalStateException(); case 4: // Use of continue statement continue; default: // For the last case, use of break statement is optional doSomethingElse(); }
See
- MITRE, CWE-484 - Omitted Break Statement in Switch
- CERT, MSC17-C. - Finish every set of statements associated with a case label with a break statement
- CERT, MSC52-J. - Finish every set of statements associated with a case label with a break statement
Define a constant instead of duplicating this literal " \"code\": \"WAITING\",
" 4 times. Open
" \"code\": \"WAITING\",\n" +
- Read upRead up
- 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.
Define a constant instead of duplicating this literal " \"walking\": \"0\",
" 6 times. Open
" \"walking\": \"0\",\n" +
- Read upRead up
- 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.
Add the missing @deprecated Javadoc tag. Open
private static String getVehicleClass(String id) {
- Read upRead up
- Exclude checks
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(); }
Add a default case to this switch. Open
switch ((int) tag) {
- Read upRead up
- Exclude checks
The requirement for a final default
clause is defensive programming. The clause should either take appropriate action, or contain a
suitable comment as to why no action is taken.
Noncompliant Code Example
switch (param) { //missing default clause case 0: doSomething(); break; case 1: doSomethingElse(); break; } switch (param) { default: // default clause should be the last one error(); break; case 0: doSomething(); break; case 1: doSomethingElse(); break; }
Compliant Solution
switch (param) { case 0: doSomething(); break; case 1: doSomethingElse(); break; default: error(); break; }
Exceptions
If the switch
parameter is an Enum
and if all the constants of this enum are used in the case
statements,
then no default
clause is expected.
Example:
public enum Day { SUNDAY, MONDAY } ... switch(day) { case SUNDAY: doSomething(); break; case MONDAY: doSomethingElse(); break; }
See
- MITRE, CWE-478 - Missing Default Case in Switch Statement
- CERT, MSC01-C. - Strive for logical completeness