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/OpenJDK 21

Interface WildcardType

All Superinterfaces:
Type
public interface WildcardType extends Type
WildcardType represents a wildcard type expression, such as ?, ? extends Number, or ? super Integer.
See Java Language Specification:
4.5.1 Type Arguments of Parameterized Types
Since:
1.5

Method Summary

Modifier and Type Method Description
Type[] getLowerBounds()
Returns an array of Type objects representing the lower bound(s) of this type variable.
Type[] getUpperBounds()
Returns an array of Type objects representing the upper bound(s) of this type variable.

Methods declared in interface java.lang.reflect.Type

getTypeName

Method Details

getUpperBounds

Type[] getUpperBounds()
Returns an array of Type objects representing the upper bound(s) of this type variable. If no upper bound is explicitly declared, the upper bound is Object.

For each upper bound B :

  • if B is a parameterized type or a type variable, it is created, (see ParameterizedType for the details of the creation process for parameterized types).
  • Otherwise, B is resolved.
API Note:
While to date a wildcard may have at most one upper bound, callers of this method should be written to accommodate multiple bounds.
Returns:
an array of Types representing the upper bound(s) of this type variable
Throws:
TypeNotPresentException - if any of the bounds refers to a non-existent type declaration
MalformedParameterizedTypeException - if any of the bounds refer to a parameterized type that cannot be instantiated for any reason

getLowerBounds

Type[] getLowerBounds()
Returns an array of Type objects representing the lower bound(s) of this type variable. If no lower bound is explicitly declared, the lower bound is the type of null. In this case, a zero length array is returned.

For each lower bound B :

  • if B is a parameterized type or a type variable, it is created, (see ParameterizedType for the details of the creation process for parameterized types).
  • Otherwise, B is resolved.
API Note:
While to date a wildcard may have at most one lower bound, callers of this method should be written to accommodate multiple bounds.
Returns:
an array of Types representing the lower bound(s) of this type variable
Throws:
TypeNotPresentException - if any of the bounds refers to a non-existent type declaration
MalformedParameterizedTypeException - if any of the bounds refer to a parameterized type that cannot be instantiated for any reason

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/reflect/WildcardType.html