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### class:MatchException [CHANGED]
All Implemented Interfaces: `Serializable` public final class MatchException extends RuntimeException `MatchException` is a preview API of the Java platform. Programs can only use `MatchException` when preview features are enabled. Preview features may be removed in a future release, or upgraded to permanent features of the Java platform. Thrown to indicate an unexpected failure in pattern matching. `MatchException` may be thrown when an exhaustive pattern matching language construct (such as a switch expression) encounters a value that does not match any of the provided patterns at runtime. This can currentlyarise for separate from a number of cases: Separate compilation anomalies, where a sealed interface has a different set of permitted subtypes at runtime than it had at compilation time, an enum has a different set of constants at runtime than it had at compilation time, or the type hierarchy has changed in incompatible ways between compile time and run time. Null targets and sealed types. If an interface or abstract class `C` is sealed to permit `A` and `B`, then the set of record patterns `R(A a)` and `R(B b)` are exhaustive on a record `R` whose sole component is of type `C`, but neither of these patterns will match `new R(null)` . Null targets and nested record patterns. Given a record type `R` whose sole component is `S`, which in turn is a record whose sole component is `String`, then the nested record pattern `R(S(String s))` will not match `new R(null)` . Match failures arising from unexpected inputs will generally throw `MatchException` only after all patterns have been tried; even if `R(S(String s))` does not match `new R(null)` , a later pattern (such as `R r` ) may still match the target. MatchException may also be thrown when operations performed as part of pattern matching throw an unexpected exception. For example, pattern matching may cause methods such as record component accessors to be implicitly invoked in order to extract pattern bindings. If these methods throw an exception, execution of the pattern matching construct may fail with `MatchException`. See Java Language Specification : 14.11.3 Execution of a switch Statement 14.30.2 Pattern Matching 15.28.2 Run-Time Evaluation of switch Expressions Since: 19 See Also: Serialized Form
All Implemented Interfaces: `Serializable` public final class MatchException extends RuntimeException `MatchException` is a preview API of the Java platform. Programs can only use `MatchException` when preview features are enabled. Preview features may be removed in a future release, or upgraded to permanent features of the Java platform. Thrown to indicate an unexpected failure in pattern matching. `MatchException` may be thrown when an exhaustive pattern matching language construct (such as a switch expression) encounters a value that does not match any of the provided patterns at runtime. This can currently arise for separate compilation anomalies, where a sealed interface has a different set of permitted subtypes at runtime than it had at compilation time, an enum has a different set of constants at runtime than it had at compilation time, or the type hierarchy has changed in incompatible ways between compile time and run time. See Java Language Specification : 14.11.3 Execution of a switch Statement 14.30.2 Pattern Matching 15.28.2 Run-Time Evaluation of switch Expressions Since: 19 See Also: Serialized Form | All Implemented Interfaces: `Serializable` public final class MatchException extends RuntimeException `MatchException` is a preview API of the Java platform. Programs can only use `MatchException` when preview features are enabled. Preview features may be removed in a future release, or upgraded to permanent features of the Java platform. Thrown to indicate an unexpected failure in pattern matching. `MatchException` may be thrown when an exhaustive pattern matching language construct (such as a switch expression) encounters a value that does not match any of the provided patterns at runtime. This can arise from a number of cases: Separate compilation anomalies, where a sealed interface has a different set of permitted subtypes at runtime than it had at compilation time, an enum has a different set of constants at runtime than it had at compilation time, or the type hierarchy has changed in incompatible ways between compile time and run time. Null targets and sealed types. If an interface or abstract class `C` is sealed to permit `A` and `B`, then the set of record patterns `R(A a)` and `R(B b)` are exhaustive on a record `R` whose sole component is of type `C`, but neither of these patterns will match `new R(null)` . Null targets and nested record patterns. Given a record type `R` whose sole component is `S`, which in turn is a record whose sole component is `String`, then the nested record pattern `R(S(String s))` will not match `new R(null)` . Match failures arising from unexpected inputs will generally throw `MatchException` only after all patterns have been tried; even if `R(S(String s))` does not match `new R(null)` , a later pattern (such as `R r` ) may still match the target. MatchException may also be thrown when operations performed as part of pattern matching throw an unexpected exception. For example, pattern matching may cause methods such as record component accessors to be implicitly invoked in order to extract pattern bindings. If these methods throw an exception, execution of the pattern matching construct may fail with `MatchException`. See Java Language Specification : 14.11.3 Execution of a switch Statement 14.30.2 Pattern Matching 15.28.2 Run-Time Evaluation of switch Expressions Since: 19 See Also: Serialized Form