Lesson: Arrays and Enumerated Types
From the Java virtual machine's perspective, arrays and enumerated types (or enums) are just classes. Many of the methods in
Class may be used on them. Reflection provides a few specific APIs for arrays and enums. This lesson uses a series of code samples to describe how to distinguish each of these objects from other classes and operate on them. Various errors are also be examined.
Arrays have a component type and a length (which is not part of the type). Arrays may be maniuplated either in their entirety or component by component. Reflection provides the
java.lang.reflect.Array class for the latter purpose.
- Identifying Array Types describes how to determine if a class member is a field of array type
- Creating New Arrays illustrates how to create new instances of arrays with simple and complex component types
- Getting and Setting Arrays and Their Components shows how to access fields of type array and individually access array elements
- Troubleshooting covers common errors and programming misconceptions
Enums are treated very much like ordinary classes in reflection code.
Class.isEnum() tells whether a
Class represents and
Class.getEnumConstants() retrieves the enum constants defined in an enum.
java.lang.reflect.Field.isEnumConstant() indicates whether a field is an enumerated type.