Excluding warnings using @SuppressWarnings

Since Java 5.0, you can disable compilation warnings relative to a subset of a compilation unit using the java.lang.SuppressWarning annotation.

 @SuppressWarning("unused") public void foo() {
  String s;
 }

Without the annotation, the compiler would complain that the local variable s is never used. With the annotation, the compiler silently ignores this warning locally to the foo method. This enables to keep the warnings in other locations of the same compilation unit or the same project.

The list of tokens that can be used inside a SuppressWarnings annotation is:

• 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)
• javadoc to suppress warnings relative to javadoc warnings
• nls to suppress warnings relative to non-nls string literals
• null to suppress warnings relative to null analysis
• rawtypes to suppress warnings relative to usage of raw types
• resource to suppress warnings relative to usage of resources of type Closeable
• 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
• static-method to suppress warnings relative to methods that could be declared as static
• super to suppress warnings relative to overriding a method without super invocations
• synthetic-access to suppress warnings relative to unoptimized access from inner classes
• sync-override to suppress warnings because of missing synchronize when overriding a synchronized method
• 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 and dead code