![]() access and set the type field Field field1 obj. It also demonstrates attempting to get a protected field using getField(), which throws an error since getField() can't be used for protected or private fields. The Java reflection field class is used to perform modifications on a class's fields facilitated through the methods of the Field class. In the non-reflection equivalent Integer val 42, the compiler would convert (or box) the primitive type 42 to a reference type as new Integer (42) so that its type. tInt () is invoked to set a field that is of the reference type Integer with a value of primitive type. ![]() This is demonstrated in the ClassFieldTest object, which sets and gets a field in FieldTest and also sets and gets a field that FieldTest inherits from ParentFieldTest. The FieldTrouble example will generate an IllegalArgumentException. can be used to get/set fields (member variables) at runtime using reflection. You still cant access the field using normal code. Now you can access it even if it is private, protected or package scope, even if the caller is not part of those scopes. To get the value of a public field, you can call the get() method of the Field object, with the object featuring the field value that you'd like to get as the first parameter. By calling tAcessible (true) you turn off the access checks for this particular Field instance, for reflection only. There are other 'set' methods for primitive (non-object) field types. You can set the value of the field by calling the set() method on the Field object, where the first parameter is the object that has the field value that you'd like to set, and the second parameter is the value of that field. You can call getField() on the Class object to get a Field object for a public field of the class, including inherited public fields. For example, it's possible for a Java class to obtain the names of all its members and display them. It allows an executing Java program to examine or 'introspect' upon itself, and manipulate internal properties of the program. If you have an object in Java S W, you can get its Class object by calling getClass() on the object. Reflection is a feature in the Java programming language. ![]()
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