Always remember! Whenever reflection is used, the security of the application is compromised. It is an advanced feature that should only be used by programmers or developers who have a good knowledge of the basics of the language. Conclusionīecause of the above-mentioned cons, it is generally advisable to avoid using reflection. Why its so important to have Answer: Java Reflection API provides the ability to inspect and modify the runtime behavior of java application. Reflection in Java is fundamentally a Runtime API that helps track changes in the behavior of Classes and Objects contained within the Class, methods, and. Therefore, the operations performed by reflections are usually slow. Since the types in reflection are resolved dynamically, JVM (Java Virtual Machine) optimization cannot take place. For example, if one access the private members of a class and sets null value to it, then the other user of the same class can get the NullReferenceException, and this behaviour is not expected.Īnother demerit is the overhead in performance. Thus, reflection may leak important data to the outside world, which is dangerous. It is possible to access the private methods and fields of a class using reflection.
is operators are used to check the object with type. What is the difference between as and is operators in C A: as operators are used to cast the object to class. It helps in the creation of Visual Development Environments and class browsers which provides aid to the developers to write the correct code.Ĭons: Using reflection, one can break the principles of encapsulation. A: The uses of the property are validating data before allocating it to a field and logging all access for a child, when you need it. These frameworks must use reflection to find a method corresponding to an action name.
Java reflection interview questions and answers software#
It is also possible to call methods, instantiate a clear or to set the value of fields using reflection. Top Java Software Engineer Interview Questions And Answers Guide. Pros: Inspection of interfaces, classes, methods, and fields during runtime is possible using reflection, even without using their names during the compile time. While the reflection provides a lot of advantages, it has some disadvantages too. Java reflection should always be used with caution. Let's see the simple example of forName() method.
There are 3 ways to get the instance of Class class. Returns the total number of constructors of this class.ġ1) public Method getDeclaredMethod(String name,Class parameterTypes)throws NoSuchMethodException,SecurityException Returns the total number of methods of this class.ġ0) public Constructor getDeclaredConstructors()throws SecurityException Returns the total number of fields of this class.ĩ) public Method getDeclaredMethods()throws SecurityException Loads the class and returns the reference of Class class.ģ) public Object newInstance()throws InstantiationException,IllegalAccessExceptionĨ) public Field getDeclaredFields()throws SecurityException Commonly used methods of Class class: MethodĢ) public static Class forName(String className)throws ClassNotFoundException
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