Indicate your preferences for the Errors/Warnings settings on the Java > Compiler > Errors/Warnings preference page.
Option |
Description |
Default |
---|---|---|
Non-static access to a static member |
When enabled, the compiler will issue an error or a warning whenever a static field or method is accessed with an expression receiver. A reference to a static member should be qualified with a type name. |
Warning |
Indirect access to a static member |
When enabled, the compiler will issue an error or a warning whenever a static field or method is indirectly accessed. A static field of an interface should be qualified with the declaring type name. |
Ignore |
Unqualified access to instance field |
When enabled, the compiler will issue an error or a warning whenever it encounters a field access which is not qualified (e.g. misses a 'this'). |
Ignore |
Access to a non-accessible member of an enclosing type |
When enabled, the compiler will issue an error or a warning whenever it emulates access to a non-accessible member of an enclosing type. Such accesses can have performance implications. |
Ignore |
Parameter assignment |
Assigning a value to a parameter is generally considered poor style programming. When this option is enabled, the compiler will signal such scenario either as an error or a warning. |
Ignore |
Non-externalized strings |
When enabled, the compiler will issue an error or a warning for non externalized String literal (i.e. non tagged with //$NON-NLS-<n>$) or for non externalized String tags which do not belong to a String. |
Ignore |
Undocumented empty block |
When enabled, the compiler will issue an error or a warning whenever it encounters an empty block statement with no explaining comment. |
Ignore |
Resource not managed via try-with-resource (1.7 or higher) |
When enabled, the compiler will issue an error or a warning if a local variable holds a value of type 'java.lang.AutoCloseable', and if the method 'close()' is explicitly invoked on that resource, but the resource is not managed by a try-with-resources block. |
Ignore |
Method with a constructor name |
Naming a method with a constructor name is generally considered poor style programming. When this option is enabled, the compiler will signal such scenario either as an error or a warning. |
Warning |
Method can be static |
When enabled, the compiler will issue an error or a warning for methods which are private or final and which refer only to static members. |
Ignore |
Method can potentially be static |
When enabled, the compiler will issue an error or a warning for methods which are not private or final and which refer only to static members. Note that methods can be overridden in a subclass, so if you make a "potentially static" method static, this may break existing clients. |
Ignore |
Comparing identical values ('x == x') |
When enabled, the compiler will issue an error or a warning if a comparison is involving identical operands (e.g 'x == x'). |
Warning |
Assignment has no effect (e.g. 'x = x') |
When enabled, the compiler will issue an error or a warning whenever an assignment has no effect (e.g. 'x = x'). |
Warning |
Possible accidental boolean assignment (e.g. 'if (a = b)') |
When enabled, the compiler will issue an error or a warning whenever it encounters a possible accidental boolean assignment (e.g. 'if (a = b)'). |
Ignore |
Boxing and unboxing conversions |
When enabled, the compiler will issue an error or a warning whenever it encounters a boxing or unboxing conversion. Autoboxing may affects performance negatively. |
Ignore |
Using a char array in string concatenation |
When enabled, the compiler will issue an error or a warning whenever a char[] expression is used in String concatenations, "hello" + new char[]{'w','o','r','l','d'} |
Warning |
Inexact type match for vararg arguments |
When enabled, the compiler will issue an error or a warning whenever it encounters an inexact type match for vararg arguments. |
Warning |
Empty statement |
When enabled, the compiler will issue an error or a warning whenever it encounters an empty statement (e.g. a superfluous semicolon). |
Ignore |
Unused object allocation |
When enabled, the compiler will issue an error or a warning when it encounters an allocated object which is not used, e.g. if (name == null) new IllegalArgumentException(); |
Ignore |
Incomplete 'switch' cases on enum |
When enabled, the compiler will issue an error or a warning whenever it encounters a switch statement which does not contain case statements for every enum constant of the referenced enum nor a default case. A default case is assumed to cover missing case statements for any enum constant, so the compiler is silent in the presence of default cases unless the option "Signal even if 'default' case exists" (see below) is enabled. |
Warning |
Signal even if 'default' case exists |
When enabled, the compiler additionally will issue an error or a warning if an enum constant is not covered by a case, even if a default case exists. This options is helpful in catching missing case statements when a new enum constant is added. |
Off |
'switch' is missing 'default' case |
When enabled, the compiler will issue an error or a warning if a 'switch' statement lacks a default case. Consequently, missing 'default' will be flagged even if all possible values are otherwise covered by 'case' statements. This warning is recommended by the Java Language Specification for the sake of binary compatibility. |
Ignore |
'switch' case fall-through |
When enabled, the compiler will issue an error or a warning when a case may be entered by falling through a preceding, non empty case. |
Ignore |
Hidden catch block |
Locally to a try statement, some catch blocks may hide others , e.g. try { throw new java.io.CharConversionException(); } catch (java.io.CharConversionException e) { } catch (java.io.IOException e) {} When enabled, the compiler will issue an error or a warning for hidden catch blocks corresponding to checked exceptions. |
Warning |
'finally' does not complete normally |
When enabled, the compiler will issue an error or a warning whenever a 'finally' statement does not complete normally (e.g. contains a return statement). |
Warning |
Dead code (e.g. 'if (false)') |
When enabled, the compiler will issue an error or a warning when it encounters dead code (e.g 'if (false)' ). |
Warning |
Resource leak |
When enabled, the compiler will issue an error or a warning if a local variable holds a value of type 'java.lang.AutoCloseable' (compliance >= 1.7) or a value of type 'java.io.Closeable' (compliance <= 1.6) and if flow analysis shows that the method 'close()' is not invoked locally on that value. |
Warning |
Potential resource leak |
When enabled, the compiler will issue an error or a warning if a local variable holds a value of type 'java.lang.AutoCloseable' (compliance >= 1.7) or a value of type 'java.io.Closeable' (compliance <= 1.6) and if flow analysis shows that the method 'close()' is not invoked locally on that value for all execution paths. |
Ignore |
Serializable class without serialVersionUID |
When enabled, the compiler will issue an error or a warning whenever a type implementing 'java.io.Serializable' does not contain a serialVersionUID field. |
Warning |
Missing synchronized modifier on inherited method |
When enabled, the compiler will issue an error or a warning when it encounters an inherited method which is missing the synchronized modifier. |
Ignore |
Class overrides 'equals()' but not 'hashCode()' |
When enabled, the compiler will issue an error or a warning when it encounters a class which overrides 'equals()' but not 'hashCode()'. |
Ignore |
Field declaration hides another field or variable |
When enabled, the compiler will issue an error or a warning if a field declaration hides another inherited field. |
Ignore |
Local variable declaration hides another field or variable |
When enabled, the compiler will issue an error or a warning if a local variable declaration hides another field or variable. |
Ignore |
Include constructor or setter method parameters |
When enabled, the compiler additionally will issue an error or a warning if a constructor or setter method parameter hides another field or variable. |
Off |
Type parameter hides another type |
When enabled, the compiler will issue an error or a warning if i.e. a type parameter of an inner class hides an outer type. |
Warning |
Method does not override package visible method |
A package default method is not visible in a different package, and thus cannot be overridden. When this option is enabled, the compiler will signal such scenario either as an error or a warning. |
Warning |
Interface method conflicts with protected 'Object' method |
When enabled, the compiler will issue an error or a warning whenever an interface defines a method incompatible with a non-inherited Object method. Until this conflict is resolved, such an interface cannot be implemented, e.g. interface I { int clone(); } |
Warning |
Deprecated API |
When enabled, the compiler will signal use of deprecated API either as an error or a warning. |
Warning |
Signal use of deprecated API inside deprecated code |
When enabled, the compiler will signal use of deprecated API inside deprecated code. The severity of the problem is controlled with option "Deprecated API". |
Off |
Signal overriding or implementing deprecated method |
When enabled, the compiler will signal overriding or implementing a deprecated method The severity of the problem is controlled with option "Deprecated API". |
Off |
Forbidden reference (access rules) |
When enabled, the compiler will signal a forbidden reference specified in the access rules. |
Error |
Discouraged reference (access rules) |
When enabled, the compiler will signal a discouraged reference specified in the access rules. |
Warning |
Value of local variable is not used |
When enabled, the compiler will issue an error or a warning whenever a local variable is declared but its value is never used within its scope. |
Warning |
Value of parameter is not used |
When enabled, the compiler will issue an error or a warning whenever a parameter is declared but its value is never used within its scope. |
Ignore |
Ignore in overriding and implementing methods |
When enabled, the compiler will not issue an error or a warning whenever a parameter is declared but never used within its scope in a method that overrides or implements another method. |
On |
Ignore parameters documented with '@param' tag |
When enabled, the compiler will not issue an error or a warning whenever an unread parameter is documented with an '@param' tag. |
On |
Unused import |
When enabled, the compiler will issue an error or a warning for unused import reference. |
Warning |
Unused private member |
When enabled, the compiler will issue an error or a warning whenever a private member is declared but never used within the same unit. |
Warning |
Unnecessary 'else' statement |
When enabled, the compiler will issue an error or a warning whenever it encounters an unnecessary else statement (e.g. if (condition) return; else doSomething();). |
Ignore |
Unnecessary cast or 'instanceof' operation |
When enabled, the compiler will issue an error or a warning whenever it encounters an unnecessary cast or 'instanceof' operation (e.g. if (object instanceof Object) return;). |
Ignore |
Unnecessary declaration of thrown exception |
When enabled, the compiler will issue an error or a warning whenever it encounters an unnecessary declaration of a thrown exception. |
Ignore |
Ignore in overriding and implementing methods |
When enabled, the compiler will not issue an error or a warning whenever it encounters an unnecessary declaration of a thrown exception in a method that overrides or implements another method. |
On |
Ignore exceptions documented with '@throws' or '@exception' tags |
When enabled, the compiler will not issue an error or a warning whenever an unnecessary declaration of a thrown exception is documented with an '@throws' or '@exception' tag. |
On |
Ignore 'Exception' and 'Throwable' |
When enabled, the compiler will not issue an error or a warning whenever it encounters an unnecessary declaration of 'Exception' and 'Throwable' exception |
On |
Unused 'break' or 'continue' label |
When enabled, the compiler will issue an error or a warning whenever it encounters an unused 'break' or 'continue' label. |
Warning |
Redundant super interface |
When enabled, the compiler will issue an error or a warning whenever it encounters a type which explicitly implements an interface that is already implemented by any of its supertypes. |
Ignore |
Unchecked generic type operation |
When enabled, the compiler will issue an error or a warning whenever it encounters an unchecked generic type operation. |
Warning |
Usage of a raw type |
When enabled, the compiler will issue an error or a warning whenever it encounters a usage of a raw type (e.g. List instead of List<String>). |
Warning |
Generic type parameter declared with a final type bound |
When enabled, the compiler will issue an error or a warning whenever it encounters a type bound involving a final type. |
Warning |
Ignore unavoidable generic type problems |
When enabled, the compiler will issue an error or a warning even when it detects a generic type problem that could not have been avoided by the programmer. As an example, a type may be forced to use raw types in its method signatures and return types because the methods it overrides from a super type are declared to use raw types in the first place. Once the referenced raw APIs get generified, you either see no problem at all (if your generic types were right) or compile errors (if the API was generified in a different way). |
Off |
Missing '@Override' annotation |
When enabled, the compiler will issue an error or a warning whenever it encounters a method overriding another implemented method, and the '@Override' annotation is missing. |
Ignore |
Include implementations of interface methods (1.6 or higher) |
When enabled, the compiler will also issue an error or a warning whenever it encounters a method overriding or implementing
a method declared in an interface, and the '@Override' annotation is missing. |
On |
Missing '@Deprecated' annotation |
When enabled, the compiler will issue an error or a warning whenever it encounters a deprecated type without additional '@Deprecated' annotation. |
Ignore |
Annotation is used as super interface |
When enabled, the compiler will issue an error or a warning whenever it encounters a type implementing an annotation. Although possible, this is considered bad practice. |
Warning |
Unhandled token in '@SuppressWarnings' |
When enabled, the compiler will issue an error or a warning whenever it encounters an unknown token in a '@SuppressWarnings' annotation. |
Warning |
Enable '@SuppressWarnings' annotations |
When enabled, the compiler will process '@SuppressWarnings' annotations. When disabled, it will act as if all '@SuppressWarnings' annotations were removed. |
On |
Unused '@SuppressWarnings' token |
When enabled, the compiler will issue an error or a warning whenever it encounters an unused token in a '@SuppressWarnings' annotation. |
Warning |
Suppress optional errors with '@SuppressWarnings' |
When enabled, the '@SuppressWarnings' annotation will also suppress optional compile errors, i.e. options set to "Error" here. Mandatory compile errors cannot be suppressed. |
Off |
Null pointer access |
When enabled, the compiler will issue an error or a warning when it encounters that a local variable which is certainly null is dereferenced. Note that the analysis can not find all null pointer accesses, see Potential null pointer access. |
Warning |
Potential null pointer access |
When enabled, the compiler will issue an error or a warning when it encounters that a local variable which may be null is dereferenced. Note that the analysis is fairly conservative, it only considers cases where there is something suspicious. The quality of the analysis can be improved by using null-annotations, which can be enabled using the option Enable annotation-based null analysis |
Ignore |
Redundant null check |
When enabled, the compiler will issue an error or a warning whenever a local variable which can not be null is tested for null. |
Ignore |
Include 'assert' in null analysis |
When enabled, the compiler will honor 'assert' statement when doing the null analysis. |
Off |
Enable annotation-based null analysis |
When enabled, the compiler will interpret annotations @Nullable, @NonNull, and @NonNullByDefault as specifying whether or not a given type includes the value 'null'. The effect of these analyses is further controlled by the following sub-options. See also Using null annotations. |
Off |
Violation of null specification |
Depending on this option, the compiler will issue either an error or a warning whenever one of the following situations is detected:
In the above an expression is considered as nullable if
either it is statically known to evaluate to the value |
Error |
Conflict between null annotations and null inference |
Depending on this option, the compiler will issue either an error or a warning whenever one of the following situations is detected:
|
Error |
Unchecked conversion from non-annotated type to @NonNull type |
Depending on this option, the compiler will issue either an error or a warning whenever one of the following situations is detected:
Unchecked conversion is usually a consequence of using other unannotated variables or methods. |
Warning |
Redundnant null annotation |
When enabled, the compiler will issue an error or a warning when a non-null annotation is applied although the same effect is already achieved by a default applicable at the current location. Such a default may be set by enabling the option Use non-null as workspace-wide (or project-wide) default or by using the @NonNullByDefault annotation. |
Warning |
Missing '@NonNullByDefault' annotation on package |
When enabled, the compiler will issue an error or a warning in the following cases:
|
Ignore |
Use default annotations for null specifications |
When enabled, the compiler will use the default set of annotations for null specifications. These annotations are included in the Eclipse SDK in the org.eclipse.jdt.annotation bundle. You can specify different annotation names to use in your projects, but be aware that the Eclipse compiler only supports the semantics specified in the default annotations:
|
On |
When Treat above errors like fatal compile errors is enabled, all generated errors, fatal or configurable, lead to non-executable code. If disabled, then your code can be executed as long as it has no fatal error (syntax error, type error, or any error according to the Java Language Specification).