Showing 2,278 of 2,280 total issues
Remove this unused "USED_LIBRARIES" private field. Open
private static final Map<String, String> USED_LIBRARIES = Map.of(
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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.
This block of commented-out lines of code should be removed. Open
//Graphics2D graphics2D = cb.createGraphicsShapes(captionBounds.width, captionBounds.height, true, 0.95f);
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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
//PdfCaption textFieldCaption = widget.getCaptionComponent();
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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.
Refactor the code in order to not assign to this loop counter from within the loop body. Open
i = -1;
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A for
loop stop condition should test the loop counter against an invariant value (i.e. one that is true at both the beginning and
ending of every loop iteration). Ideally, this means that the stop condition is set to a local variable just before the loop begins.
Stop conditions that are not invariant are slightly less efficient, as well as being difficult to understand and maintain, and likely lead to the introduction of errors in the future.
This rule tracks three types of non-invariant stop conditions:
- When the loop counters are updated in the body of the
for
loop - When the stop condition depend upon a method call
- When the stop condition depends on an object property, since such properties could change during the execution of the loop.
Noncompliant Code Example
for (int i = 0; i < 10; i++) { ... i = i - 1; // Noncompliant; counter updated in the body of the loop ... }
Compliant Solution
for (int i = 0; i < 10; i++) {...}
This block of commented-out lines of code should be removed. Open
// for (final JMenuItem menuItem: closeItems) {
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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
// setCloseState(state);
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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
// if (widgets.isEmpty()) {
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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
// for (final JMenuItem menu: alignAndOrderMenuItems) {
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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
// selectedWidget.setX((int) ((widgetLastX + mouseX) / scale));
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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.
Refactor the code in order to not assign to this loop counter from within the loop body. Open
i = -1;
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A for
loop stop condition should test the loop counter against an invariant value (i.e. one that is true at both the beginning and
ending of every loop iteration). Ideally, this means that the stop condition is set to a local variable just before the loop begins.
Stop conditions that are not invariant are slightly less efficient, as well as being difficult to understand and maintain, and likely lead to the introduction of errors in the future.
This rule tracks three types of non-invariant stop conditions:
- When the loop counters are updated in the body of the
for
loop - When the stop condition depend upon a method call
- When the stop condition depends on an object property, since such properties could change during the execution of the loop.
Noncompliant Code Example
for (int i = 0; i < 10; i++) { ... i = i - 1; // Noncompliant; counter updated in the body of the loop ... }
Compliant Solution
for (int i = 0; i < 10; i++) {...}
Add a nested comment explaining why this method is empty, throw an UnsupportedOperationException or complete the implementation. Open
public void setResizeFromTopRatio(final double resizeHeightRatio) {
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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 } }
Add a nested comment explaining why this method is empty, throw an UnsupportedOperationException or complete the implementation. Open
public void setObjectProperties() {
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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 } }
Refactor the code in order to not assign to this loop counter from within the loop body. Open
i = size + 1;
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A for
loop stop condition should test the loop counter against an invariant value (i.e. one that is true at both the beginning and
ending of every loop iteration). Ideally, this means that the stop condition is set to a local variable just before the loop begins.
Stop conditions that are not invariant are slightly less efficient, as well as being difficult to understand and maintain, and likely lead to the introduction of errors in the future.
This rule tracks three types of non-invariant stop conditions:
- When the loop counters are updated in the body of the
for
loop - When the stop condition depend upon a method call
- When the stop condition depends on an object property, since such properties could change during the execution of the loop.
Noncompliant Code Example
for (int i = 0; i < 10; i++) { ... i = i - 1; // Noncompliant; counter updated in the body of the loop ... }
Compliant Solution
for (int i = 0; i < 10; i++) {...}
Define a constant instead of duplicating this literal "Text Field" 3 times. Open
final String widgetName = "Text Field" + textFieldNextWidgetNumber;
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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 "Caption and Value" 7 times. Open
"Caption and Value",
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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.
Add a nested comment explaining why this method is empty, throw an UnsupportedOperationException or complete the implementation. Open
public void removeSelectedWidgets() {
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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 } }
Add a nested comment explaining why this method is empty, throw an UnsupportedOperationException or complete the implementation. Open
public void setDragBoxLocation(final Point dragBoxLocation) {
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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 } }
Add a nested comment explaining why this method is empty, throw an UnsupportedOperationException or complete the implementation. Open
public void repaint(
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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 } }
This block of commented-out lines of code should be removed. Open
// if (widget.getType() == IWidget.IMAGE) {
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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.
Rename "widgets" which hides the field declared at line 36. Open
final List<IWidget> widgets = mainFrame.getFormsDocument().getPage(mainFrame.getCurrentPage()).getWidgets();
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Overriding or shadowing a variable declared in an outer scope can strongly impact the readability, and therefore the maintainability, of a piece of code. Further, it could lead maintainers to introduce bugs because they think they're using one variable but are really using another.
Noncompliant Code Example
class Foo { public int myField; public void doSomething() { int myField = 0; ... } }
See
- CERT, DCL01-C. - Do not reuse variable names in subscopes
- CERT, DCL51-J. - Do not shadow or obscure identifiers in subscopes