![]() The getFields() methods returns an array consisting of objects which display all the public attributes of the invoking class or interface. getFields() and getDeclaredFields() methods: Thus you can see that the getMethods() method returns all the public methods of the object including superclasses, whereas getDeclaredMethods() only returned user-declared methods. The syntax for the forName method is as follows: ![]() This method accepts the full qualified name of a class or an interface as an argument and returns an instance of the class associated with the qualifed name, including all its attributes and behaviours. Some of these methods are: forName() method: ![]() ![]() The Class class has a wide variety of methods that are useful in obtaining a reflection of the class executing and performing a wide range of actions with that class. Using an instance of Class, we can view, analyse and modify the attributes of a class while it is running, and can even invoke methods of that class. An instance of the class Class is used to represent both classes and interfaces in a Java application which is running. The Class is a final class in the java.lang package of Java’s standard library, and extends the Object class which forms the basis of all classes in java. Now that we have had an overview of the basic idea of Reflection, let us go through the class which plays the most significant role in reflection in java. Exposure of Internal Fields and Attributesĭue to the ability of Reflection API to access private members and invoke private functions, the internal details of classes and entities are exposed to the outside world and defeats the purpose of Abstraction in object oriented concepts, which may be seen as a violation of object oriented programming concepts. Also, the security permission requirements can pose a threat to code residing in a secure system. Reflection API requires cetain security permissions that are not available during execution under a securely managed system. As it tends to slow down processing, it isn’t recommended for use in sections of code that require high availability and low turnaround. This is because many functionalities make use of dynamic resolution which prevents to the use of certain Virtual machine optimisations. The use of reflection API can lead to high performance overhead and lead to lower performance. Inspite of being an extremely powerful tool, Reflection API and its usage does have a set of disadvantages such as, Low Performace Debugging and Testing toolsĭebugging requires the ability to view internal details of a class which include its private members.Debugging and Testing tools may use reflection to make systematic invocations to the classes by use of reflection and ensure test case coverage. Using these, the visual development environments make the information of the classes readily available to the user so that they can write proper code. IDEs, especially those which are capable of visual development, such as Eclipse or Netbeans, and class browsers can make extensive use of Reflection. Using the concepts of reflection, a programmer can make use of externally available user-defined classes by creating instances of those extensible objects by using their fully qualified name Developing IDEs and Class Browsers Other than these, the class is one of the most important classes in use for Reflection as the objects of Class can store the actual information of the class that we want to investigate or reflect. Reflection is heavily used in Java frameworks such as Spring, Hibernate, Junit etc. Using the concept of Reflection, a programmer can now manipulate all attributes of a class – including its methods, constructors, and fields even at runtime, and even invoke methods of that class and get a complete snapshot of it. In Java, the process of analyzing, viewing and modifying all the internal attributes, behaviors and capabilities of a class at runtime is called Reflection. getFields() and getDeclaredFields() methods:.getConstructors() and getDeclaredConstructors() methods:.Exposure of Internal Fields and Attributes.
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