Supported Values for @SuppressWarnings & How to use @SuppressWarnings

Supported Values for @SuppressWarnings

http://jinchun1223.javaeye.com/blog/454140
http://www.breakitdownblog.com/supported-values-for-suppresswarnings/

Update #1: All these annotations are still valid in Eclipse 3.4 and 3.5, there have been no new SuppressWarning arguments added in those versions of the JDT compiler.

If you are a Java developer and use the new @SuppressWarnings annotation in your code from time-to-time to suppress compiler warnings you, like me, have wondered probably about a million times already just exactly what are the supported values that can be used with this annotation.

The reason the list isn’t easy to find is because it’s compiler specific, which means Sun may have a different set of supported values than say IBM, GCJ or Apache Harmony.

Fortunately for us, the Eclipse folks have documented the values they support (As of Eclipse 3.3), here they are for reference:

* all to suppress all warnings
* boxing to suppress warnings relative to boxing/unboxing operations
* cast to suppress warnings relative to cast operations
* dep-ann to suppress warnings relative to deprecated annotation
* deprecation to suppress warnings relative to deprecation
* fallthrough to suppress warnings relative to missing breaks in switch statements
* finally to suppress warnings relative to finally block that don’t return
* hiding to suppress warnings relative to locals that hide variable
* incomplete-switch to suppress warnings relative to missing entries in a switch statement (enum case)
* nls to suppress warnings relative to non-nls string literals
* null to suppress warnings relative to null analysis
* restriction to suppress warnings relative to usage of discouraged or forbidden references
* serial to suppress warnings relative to missing serialVersionUID field for a serializable class
* static-access to suppress warnings relative to incorrect static access
* synthetic-access to suppress warnings relative to unoptimized access from inner classes
* unchecked to suppress warnings relative to unchecked operations
* unqualified-field-access to suppress warnings relative to field access unqualified
* unused to suppress warnings relative to unused code

TIP: For the folks that haven’t used @SuppressWarnings before, the syntax looks like this:

@SuppressWarnings(”unused”)

and can be placed above almost any piece of code that is causing a compiler warning to popup for your class.

How to use @SuppressWarnings

Sometimes you will got the warning in Java when you are using the eclipse. And this is kind of annoying. Now you can use this to eliminate it:

@SuppressWarnings(option)

This can be categorized into two categories:

• Put this notation right before the code with warning:
• • @SuppressWarnings("unused") String unused = "never";
• Put this notation right before the class declaration
• • @SuppressWarnings("deprecation ")
  • class DeprecationExample{ ... }

I think the warning options in red should be categoried into category 2.

You can simply try this out!

Warning options

-warn: allDeprecation allJavadoc assertIdentifier boxing charConcat conditionAssign constructorName dep-ann deprecation discouraged emptyBlock enumSwitch fallthrough fieldHiding finalBound finally forbidden hiding incomplete-switch indirectStatic intfAnnotation intfNonInherited javadoc localHiding maskedCatchBlocks nls noEffectAssign null over-ann paramAssign pkgDefaultMethod raw semicolon serial specialParamHiding static-access staticReceiver suppress synthetic-access syntheticAccess tasks(<task1>|...|<taskN>) typeHiding unchecked unnecessaryElse unqualified-field-access unqualifiedField unused unusedArgument unusedImport unusedLabel unusedLocal unusedPrivate unusedThrown uselessTypeCheck varargsCast warningToken

Set warning level. e.g. -warn:unusedLocal,deprecation In red are the default settings. -warn:none disable all warnings -warn:<warnings separated by ,> enable exactly the listed warnings -warn:+<warnings separated by ,> enable additional warnings -warn:-<warnings separated by ,> disable specific warnings allDeprecation allJavadoc assertIdentifier boxing charConcat conditionAssign constructorName dep-ann deprecation discouraged emptyBlock enumSwitch, incomplete-switch fallthrough fieldHiding finalBound finally forbidden hiding indirectStatic intfAnnotation intfNonInherited javadoc localHiding maskedCatchBlocks nls noEffectAssign null over-ann paramAssign pkgDefaultMethod raw semicolon serial specialParamHiding static-access staticReceiver suppress syntheticAccess, synthetic-access tasks typeHiding unchecked unnecessaryElse unqualified-field-access, unqualifiedField unused unusedArgument unusedImport unusedLabel unusedLocal unusedPrivate unusedThrown uselessTypeCheck varargsCast warningToken deprecation even inside deprecated code invalid or missing javadoc occurrence of assert used as identifier autoboxing conversion when a char array is used in a string concatenation without being converted explicitly to a string possible accidental boolean assignment method with constructor name missing @Deprecated annotation usage of deprecated type or member outside deprecated code use of types matching a discouraged access rule undocumented empty block incomplete enum switch possible fall-through case field hiding another variable type parameter with final bound finally block not completing normally use of types matching a forbidden access rule macro for fieldHiding, localHiding, typeHiding and maskedCatchBlock indirect reference to static member annotation type used as super interface interface non-inherited method compatibility invalid javadoc local variable hiding another variable hidden catch block non-nls string literals (lacking of tags //$NON-NLS-<n>) assignment with no effect missing or redundant null check missing @Override annotation assignment to a parameter attempt to override package-default method usage a of raw type (instead of a parametrized type) unnecessary semicolon or empty statement missing serialVersionUID constructor or setter parameter hiding another field macro for indirectStatic and staticReceiver if a non static receiver is used to get a static field or call a static method enable @SuppressWarnings when performing synthetic access for innerclass enable support for tasks tags in source code type parameter hiding another type unchecked type operation unnecessary else clause unqualified reference to field macro for unusedArgument, unusedImport, unusedLabel, unusedLocal, unusedPrivate and unusedThrown unused method argument unused import reference unused label unused local variable unused private member declaration unused declared thrown exception unnecessary cast/instanceof operation varargs argument need explicit cast unhandled warning token in @SuppressWarnings