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| <h1>Java Compile Errors/Warnings Preferences</h1> |
| <p>Indicate your preferences for the Errors/Warnings settings on the <a class="command-link" href='javascript:executeCommand("org.eclipse.ui.window.preferences(preferencePageId=org.eclipse.jdt.ui.preferences.ProblemSeveritiesPreferencePage)")'> <img src="PLUGINS_ROOT/org.eclipse.help/command_link.png" alt="Opens the Errors/Warnings preference page"> <b> Java > Compiler > Errors/Warnings </b></a> preference page.</p> |
| <h3>Code style</h3> |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Code style section"> |
| <tr> |
| <th> |
| <p>Option</p> |
| </th> |
| <th> |
| <p>Description</p> |
| </th> |
| <th> |
| <p>Default</p> |
| </th> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Non-static access to a static member</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Indirect access to a static member</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unqualified access to instance field</p> |
| </td> |
| <td valign="top"> |
| <p>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').</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Access to a non-accessible member of an enclosing type</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Parameter assignment</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Non-externalized strings</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Undocumented empty block</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an empty block statement with no explaining comment.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Resource not managed via try-with-resource (1.7 or higher)</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Method with a constructor name</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Method can be static</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Method can potentially be static</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| </table> |
| |
| <h3>Potential programming problems</h3> |
| |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Potential programming problems section"> |
| <tr> |
| <td valign="top"> |
| <p>Comparing identical values ('x == x')</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning if a comparison is involving identical operands (e.g 'x == x').</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Assignment has no effect (e.g. 'x = x')</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever an assignment has no effect (e.g. 'x = x').</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Possible accidental boolean assignment (e.g. 'if (a = b)')</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters a possible accidental boolean assignment (e.g. 'if (a = b)').</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Boxing and unboxing conversions</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters a boxing or unboxing conversion. Autoboxing may affects performance negatively.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Using a char array in string concatenation</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever a char[] expression is used in String concatenations,</p> |
| <code>"hello" + new char[]{'w','o','r','l','d'}</code></td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Inexact type match for vararg arguments</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an inexact type match for vararg arguments.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Empty statement</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an empty statement (e.g. a superfluous semicolon).</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unused object allocation</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning when it encounters an allocated object which is not used, e.g.</p> |
| <code>if (name == null)</code><br> |
| <code> new IllegalArgumentException();</code><br> |
| <br> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr id="switch"> |
| <td valign="top"> |
| <p>Incomplete 'switch' cases on enum</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters a 'switch' statement which does not contain |
| a 'default' case nor case statements for every enum constant of the referenced enum.</p> |
| <p>This warning is recommended by the Java Language Specification |
| <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.11">14.11</a>. |
| It helps to ensure that 'switch' statements cover all possible enum values.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr id="missing_case_despite_default"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Signal even if 'default' case exists</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| <p>This option helps to catch missing case statements when a new enum constant is added.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>'switch' is missing 'default' case</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning if a 'switch' statement lacks a 'default' case. |
| Consequently, a missing 'default' will be flagged even if all possible values are otherwise covered by 'case' statements.</p> |
| <p>This option helps to ensure that new 'switch' expression values are handled explicitly, rather than being skipped. |
| It can also help to explain compile errors for un-initialized variables after a 'switch' statement: The set of legal values |
| can grow in the future, so the variable also needs to be initialized in the 'default' case.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>'switch' case fall-through</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Hidden catch block</p> |
| </td> |
| <td valign="top"> |
| <p>Locally to a try statement, some catch blocks may hide others , e.g.</p> |
| <code>try { throw new java.io.CharConversionException();</code><br> |
| <code>} catch (java.io.CharConversionException e) {</code><br> |
| <code>} catch (java.io.IOException e) {}</code><br> |
| <br> |
| <p>When enabled, the compiler will issue an error or a warning for hidden catch blocks corresponding to checked exceptions.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>'finally' does not complete normally</p> |
| </td> |
| <td valign="top"> |
| <p>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).</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Dead code (e.g. 'if (false)')</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning when it encounters dead code (e.g 'if (false)' ).</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr id="resource-leak"> |
| <td valign="top"> |
| <p>Resource leak</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Potential resource leak</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Serializable class without serialVersionUID</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever a type implementing 'java.io.Serializable' does not contain a serialVersionUID field.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Missing synchronized modifier on inherited method</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning when it encounters an inherited method which is missing the synchronized modifier.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Class overrides 'equals()' but not 'hashCode()'</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning when it encounters a class which overrides 'equals()' but not 'hashCode()'.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| </table> |
| |
| <h3>Name shadowing and conflicts</h3> |
| |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Name shadowing and conflicts section"> |
| <tr> |
| <td valign="top"> |
| <p>Field declaration hides another field or variable</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning if a field declaration hides another inherited field.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Local variable declaration hides another field or variable</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning if a local variable declaration hides another field or variable.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Include constructor or setter method parameters</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler additionally will issue an error or a warning if a constructor or setter method parameter hides another field or variable.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Type parameter hides another type</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Method does not override package visible method</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Interface method conflicts with protected 'Object' method</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| <code>interface I {</code><br> |
| <code> int clone();</code><br> |
| <code>}</code><br> |
| <br> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| </table> |
| |
| <h3>Deprecated and restricted API</h3> |
| |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Deprecated and restricted API section"> |
| <tr> |
| <td valign="top"> |
| <p>Deprecated API</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will signal use of deprecated API either as an error or a warning.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Signal use of deprecated API inside deprecated code</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will signal use of deprecated API inside deprecated code. The severity of the problem is controlled with option "Deprecated API".</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Signal overriding or implementing deprecated method</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will signal overriding or implementing a deprecated method The severity of the problem is controlled with option "Deprecated API".</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Forbidden reference (access rules)</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will signal a forbidden reference specified in the access rules.</p> |
| </td> |
| <td valign="top"> |
| <p>Error</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Discouraged reference (access rules)</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will signal a discouraged reference specified in the access rules.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| </table> |
| |
| <h3>Unnecessary code</h3> |
| |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Unnecessary code section"> |
| <tr> |
| <td valign="top"> |
| <p>Value of local variable is not used</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Value of method parameter is not used</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever a method parameter is declared but its value is never used within its scope.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Ignore in overriding and implementing methods</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unused type parameter</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning for unused type parameter.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Ignore parameters documented with '@param' tag</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will not issue an error or a warning whenever an unread parameter is documented with an '@param' tag.</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Value of exception parameter is not used</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning for unused exception parameter.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unused import</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning for unused import reference.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unused private member</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever a private member is declared but never used within the same unit.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unnecessary 'else' statement</p> |
| </td> |
| <td valign="top"> |
| <p>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();).</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unnecessary cast or 'instanceof' operation</p> |
| </td> |
| <td valign="top"> |
| <p>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;).</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unnecessary declaration of thrown exception</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an unnecessary declaration of a thrown exception.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Ignore in overriding and implementing methods</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Ignore exceptions documented with '@throws' or '@exception' tags</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Ignore 'Exception' and 'Throwable'</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will not issue an error or a warning whenever it encounters an unnecessary declaration of 'Exception' and 'Throwable' exception</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unused 'break' or 'continue' label</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an unused 'break' or 'continue' label.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Redundant super interface</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| </table> |
| |
| <h3>Generic types</h3> |
| |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Generic types section"> |
| <tr> |
| <td valign="top"> |
| <p>Unchecked generic type operation</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an unchecked generic type operation.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Usage of a raw type</p> |
| </td> |
| <td valign="top"> |
| <p>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>).</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Generic type parameter declared with a final type bound</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters a type bound involving a final type.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Ignore unavoidable generic type problems due to raw APIs</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will ignore generics-related type problems |
| that could not have been avoided by the programmer, because a referenced API already contains raw types. |
| 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.</p> |
| <p>When the old API is eventually generified, then most of these problems either go away, |
| or you will see a compile error because the type arguments you used are not correct. |
| For raw references in method signatures, the raw type problem will reappear.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| </table> |
| |
| <h3>Annotations</h3> |
| |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Annotations section"> |
| <tr> |
| <td valign="top"> |
| <p>Missing '@Override' annotation</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Include implementations of interface methods (1.6 or higher)</p> |
| </td> |
| <td valign="top"> |
| <p>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.<br> |
| Note that '@Override' is only allowed on such methods if the compiler compliance level is 1.6 or higher, so this error or |
| warning will never appear in 1.5 code.</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Missing '@Deprecated' annotation</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters a deprecated type without additional '@Deprecated' annotation.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Annotation is used as super interface</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Unhandled token in '@SuppressWarnings'</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an unknown token in a '@SuppressWarnings' annotation.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Enable '@SuppressWarnings' annotations</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will process '@SuppressWarnings' annotations. When disabled, it will act as if all '@SuppressWarnings' annotations were removed.</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Unused '@SuppressWarnings' token</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever it encounters an unused token in a '@SuppressWarnings' annotation.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Suppress optional errors with '@SuppressWarnings'</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the '@SuppressWarnings' annotation will also suppress optional compile errors, i.e. options set to "Error" here. |
| Mandatory compile errors cannot be suppressed.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| </table> |
| |
| <h3 id="null_analysis">Null analysis</h3> |
| |
| <table border="1" cellspacing="0" cellpadding="5" width="100%" summary="Annotations section"> |
| <tr> |
| <td valign="top"> |
| <p>Null pointer access</p> |
| </td> |
| <td valign="top"> |
| <p>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 <strong>Potential null pointer access</strong>.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Potential null pointer access</p> |
| </td> |
| <td valign="top"> |
| <p>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.</p> |
| <p>The quality of the analysis can be improved by using null-annotations, which can be enabled using the option |
| <b>Enable annotation-based null analysis</b> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Redundant null check</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning whenever a local variable which can not be null is tested for null.</p> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Include 'assert' in null analysis</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will honor 'assert' statement when doing the null analysis.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top"> |
| <p>Enable annotation-based null analysis</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will interpret annotations @Nullable, @NonNull, and @NonNullByDefault |
| as specifying whether or not a given type includes the value 'null'.</p> |
| <p>The effect of these analyses is further controlled by the following sub-options.</p> |
| <p>See also <a href="../../../../tasks/task-using_null_annotations.htm">Using null annotations</a>.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| <tr id="null_spec_violation"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Violation of null specification</p> |
| </td> |
| <td valign="top"> |
| <p>Depending on this option, the compiler will issue either an error or a warning whenever one of the following situations is detected:</p> |
| <ol> |
| <li>A method declared with a nonnull annotation returns a <em>nullable</em> expression.</li> |
| <li>A <em>nullable</em> expression is passed as an argument in a method call where the corresponding parameter of the called method is declared with a nonnull annotation.</li> |
| <li>A <em>nullable</em> expression is assigned to a local variable that is declared with a nonnull annotation.</li> |
| <li>A method that overrides an inherited method declared with a nonnull annotation tries to relax that contract by specifying a nullable annotation (prohibition of contravariant return).</li> |
| <li>A method that overrides an inherited method which has a nullable declaration for at least one of its parameters, tries to tighten that null contract by specifying a nonnull annotation for its corresponding parameter (prohibition of covariant parameters).</li> |
| </ol> |
| <p>In the above an expression is considered as <em>nullable</em> if |
| either it is statically known to evaluate to the value <code>null</code>, or if it is |
| declared with a nullable annotation.</p> |
| </td> |
| <td valign="top"> |
| <p>Error</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Conflict between null annotations and null inference</p> |
| </td> |
| <td valign="top"> |
| <p>Depending on this option, the compiler will issue either an error or a warning whenever one of the following situations is detected:</p> |
| <ol> |
| <li>A method declared with a nonnull annotation returns an expression that is statically known to evaluate to a null value on some flow.</li> |
| <li>An expression that is statically known to evaluate to a null value on some flow is passed as an argument in a method call where the corresponding parameter of the called method is declared with a nonnull annotation. </li> |
| <li>An expression that is statically known to evaluate to a null value on some flow is assigned to a local variable that is declared with a nonnull annotation.</li> |
| </ol> |
| </td> |
| <td valign="top"> |
| <p>Error</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Unchecked conversion from non-annotated type to @NonNull type</p> |
| </td> |
| <td valign="top"> |
| <p>Depending on this option, the compiler will issue either an error or a warning whenever one of the following situations is detected:</p> |
| <ol> |
| <li>A method declared with a nonnull annotation returns an expression for which insufficient nullness information is available for statically proving that no flow will pass a null value at runtime. </li> |
| <li>An expression for which insufficient nullness information is available for statically proving that it will never evaluate to a null value at runtime is passed as an argument in a method call where |
| the corresponding parameter of the called method is declared with a nonnull annotation. </li> |
| <li>An expression for which insufficient nullness information is available for statically proving that it will never evaluate to a null value at runtime is assigned to a local variable that is declared |
| with a nonnull annotation. </li> |
| </ol> |
| <p>Unchecked conversion is usually a consequence of using other unannotated variables or methods.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr id="pessimistic_analysis"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Problems detected by pessimistic analysis for free type variables</p> |
| </td> |
| <td valign="top"> |
| <p>Unless set to "Ignore", type variables not affected by any explicit null annotation are |
| <a href="../../../../tasks/task-using_null_type_annotations.htm#pessimistic_analysis">pessimistically analysed</a> |
| in two directions: When reading a value of this type, it is assumed to be nullable. |
| When this type appears as the required type (i.e., at the left hand side of an assignment or variable initialization, |
| or as the method return type against which a return statement is being checked) |
| the type is considered to require the nonnull property.</p> |
| <p>Problems reported due to this pessimistic analysis are reported with the level given in this option.</p> |
| <p>This option is only relevant when using <a href="../../../../tasks/task-using_null_type_annotations.htm">null type annotations</a>.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr id="unsafe_interpretation_generic_legacy"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Unsafe '@Nonnull' interpretation of free type variable from library</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning against a method call if all of the following hold:</p> |
| <ul> |
| <li>The method's declared return type is a type variable without any null annotation.</li> |
| <li>For the given invocation this type variable is substituted with a nonnull type.</li> |
| <li>The type declaring the method is provided by a third-party library.</li> |
| <li>No null annotations exist for this library type, neither in its class file nor using external annotations.</li> |
| </ul> |
| <p>This particular situation leverages the option to consistently substitute all occurrences of a type variable with a nonnull type, |
| but it bears the risk that the library type may not be aware of null annotations thus lacking a necessary @Nullable annotation |
| for a particular occurrence of a type variable.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Redundant null annotation</p> |
| </td> |
| <td valign="top"> |
| <p>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 using the @NonNullByDefault annotation.</p> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr id="nonnull_annotation_dropped"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>'@NonNull' parameter not annotated in overriding method</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning against a parameter of a method that overrides an inherited method if all of the following hold:</p> |
| <ul> |
| <li>The overridden method declares the corresponding parameter as non-null.</li> |
| <li>The parameter in the overriding method has no null annotation.</li> |
| <li>The overriding method is not affected by a nullness default.</li> |
| <li>Inheritance of null annotations is disabled.</li> |
| </ul> |
| </td> |
| <td valign="top"> |
| <p>Warning</p> |
| </td> |
| </tr> |
| <tr> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Missing '@NonNullByDefault' annotation on package</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will issue an error or a warning in the following cases:</p> |
| <ol> |
| <li>When a package does not contain a default nullness annotation, as a result of missing package-info.java |
| or missing default nullness annotation in package-info.java.</li> |
| <li>When a type inside a default package does not contain a default nullness annotation.</li> |
| </ol> |
| </td> |
| <td valign="top"> |
| <p>Ignore</p> |
| </td> |
| </tr> |
| <tr id="null_annotation_names"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Use default annotations for null specifications</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will use the default set of annotations for null specifications. These annotations are included in the Eclipse SDK in the |
| <b>org.eclipse.jdt.annotation</b> bundle.</p> |
| <p>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:</p> |
| <ul> |
| <li><b>org.eclipse.jdt.annotation.Nullable</b>: A fully qualified name of a Java annotation type, which when applied to a type in a method signature, variable declaration or field declaration, |
| will be interpreted as a specification that null is a legal value in that position.<br> |
| Currently supported positions are: method parameters, method return type, local variables and fields. |
| </li> |
| <li><b>org.eclipse.jdt.annotation.NonNull</b>: A fully qualified name of a Java annotation type, which when applied to a type in a method signature, variable declaration or field declaration, |
| will be interpreted as a specification that null is <b>not</b> a legal value in that position.<br> |
| Currently supported positions are: method parameters, method return type, local variables and fields. |
| </li> |
| <li> |
| <b>org.eclipse.jdt.annotation.NonNullByDefault</b>: A fully qualified name of a Java annotation type. When applied to an element without an annotation argument, |
| all unannotated types in method signatures and field declarations within the annotated element will be treated as if they were specified with the non-null annotation.<br> |
| Only when using the default annotation type <code>org.eclipse.jdt.annotation.NonNullByDefault</code>, also the opposite effect is supported: |
| When the annotation is applied with the constant 'false' as its argument (or '{}' in the case of type annotations), |
| all corresponding defaults at outer scopes will be canceled for the annotated element. |
| </li> |
| </ul> |
| <p>The compiler supports exactly one <em>primary</em> set of annotation types for null specification. Additionally, an arbitrary number of <em>secondary</em> annotation types |
| can be configured to carry the same semantics. Secondary annotation types are supported for the sole purpose of interfacing with 3rd party code that is already specified |
| using other null annotations than the primary annotations types of the current project.</p> |
| </td> |
| <td valign="top"> |
| <p>On</p> |
| </td> |
| </tr> |
| <tr id="inherit_null_annotations"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Inherit null annotations</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will check for each method without any explicit null annotations: |
| If it overrides a method which has null annotations, it will treat the |
| current method as if it had the same annotations as the overridden method.</p> |
| <p>Annotation inheritance will use the <em>effective</em> nullness of the overridden method |
| after transitively applying inheritance and after applying any default nullness |
| at the site of the overridden method.</p> |
| <p>If different implicit null annotations (from a nonnull default and/or overridden methods) are applicable |
| to the same type in a method signature, this is flagged as an error |
| and an explicit null annotation must be used to disambiguate.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| <tr id="syntactic_null_analysis_for_fields"> |
| <td valign="top" style="padding-left: 2em;"> |
| <p>Enable syntactic null analysis for fields</p> |
| </td> |
| <td valign="top"> |
| <p>When enabled, the compiler will detect certain syntactic constellations where a null related warning against a field reference |
| would normally be raised but can be suppressed at low risk given that the same field reference was known to be non-null immediately before. |
| When using this option please see <a href="../../../../tasks/task-using_null_annotations.htm#syntactic_analysis">these hints</a>.</p> |
| </td> |
| <td valign="top"> |
| <p>Off</p> |
| </td> |
| </tr> |
| </table> |
| |
| <p>When <strong>Treat above errors like fatal compile errors</strong> 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).</p> |
| |
| <p><img src="../../../../images/ngrelc.png" alt="Related concepts" border="0"></p> |
| <p><a href="../../../../../org.eclipse.platform.doc.user/concepts/cprbview.htm">Problems View</a><br> |
| <a href="../../../../concepts/concept-quickfix-assist.htm">Quick Fix</a><br> |
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