As a Java developer, being able to effectively use reflection can be an extremely useful skill. Reflection enables programmers to access and manipulate Java classes, methods, and fields at run time. This can be useful for various tasks such as debugging, type inspection, and dynamic class loading. For these reasons, potential employers may ask questions about your experience with reflection during a job interview. To help prepare, read on to learn some of the key Java reflection interview questions you may be asked.
What is Reflection in Java Java Interview Question And Answer
What do you understand by Reflection in Java programming language?
The Java programming language comes with an API called Java Reflection that enables you to examine classes, methods, fields, etc. at runtime; without knowing their names at compile time. Reflection can be used to instantiate objects, call methods, and set field values in addition to inspecting classes and their members.
Where is Java Reflection commonly used?
Developer tools are frequently made using the Java Reflection API.
Visual Development Environments: By prompting the developer with the appropriate types and values, visual development environments use Java reflection to make the development process simpler and more effective.
Class Browsers:Class browsers inspect class and its members
Debuggers and Testing Tools:
What are the disadvantages of Reflection?
Reflection performs its work by dynamically resolving and inspecting classes and their members, which has a performance cost. The drawback of this flexibility is that it prevents some Java virtual machine optimizations from being carried out, which results in slower performance compared to regular class and method operations. Always choose the non-reflective option when performing an operation when both options are available. Reflective operations must be avoided in loops and frequently called sections of code in performance-sensitive applications.
Security Restrictions: There are certain security impacts to using Reflection. When running in an environment with a security manager, such as in an Applet, reflection requires a runtime permission that might not be available.
Internals are exposed: Using Java reflection, we can carry out some operations that are forbidden by non-reflective operations. For instance, using non-reflective operations, we can access a class’ private members, which is prohibited. This violates the object-oriented principle of abstraction and containment and results in dysfunctional, non-portable code.
Java developers have access to a potent tool called the Java Reflection API that enables them to examine and modify classes and objects in real-time. This can be helpful for a number of tasks, including making dynamic proxies and generating code as you go. In order to determine your level of knowledge and expertise, the interviewer for a Java development position will probably ask you questions about the Reflection API. This article will go over some typical Reflection API interview queries and how to respond to them.
Using Java modifiers like public, private, and protected requires the Modifier class, a utility class. Additionally, it can be used to create an integer representation of a modifier list and provides static methods for determining whether a given integer accurately represents a specific modifier. This is helpful when using reflection because it makes it simple to tell whether a specific member is public, private, or protected.
Obtaining a reference to the Method object you wish to invoke is necessary before you can proceed. You can accomplish this by calling the getMethod() method of the Class object and providing the method’s name and the types of parameters it accepts. You can call a method by calling its invoke() method, passing the object you want to call the method on, and any necessary parameters, once you have a reference to the method object.
There is no simple answer to this question. While reflection can be used to boost performance in some situations, it can also have the opposite effect. In the end, it depends on how reflection is applied and what the particular objectives are. It is typically best to avoid using reflection if performance is the main concern.
Java Reflection API can be used to determine whether a method has parameters. Use the Method class’s getParameterTypes() method to accomplish this. One Class object will be returned by this method for each type of parameter. The method has no parameters if this array’s length is 0.
FAQ
What is reflection in Java with example?
Reflection is a feature in the Java programming language. It enables a Java program that is running to examine or “introspect” upon itself and to change the program’s internal properties. For instance, a Java class could get the names of all of its members and display them.
Is reflection good in Java?
Java Reflection enables runtime inspection of classes, interfaces, fields, and methods without needing to know their names. at compile time. Reflection can also be used to invoke methods, instantiate new objects, and get/set field values.
What is Java reflection framework?
During compile time, the Java reflection concept is used to examine and modify the behavior of classes, methods, interfaces, and constructors. Most IDEs, including Eclipse, Netbeans, etc., use this API. , debugging tools like JUnit, etc.
How do you reflect an object in Java?
We must first create a Class object in order to reflect a Java class. Additionally, by using the object, we can call different methods to learn more about the constructors, fields, and methods that are present in a class. class Dog {. Class a = Class; // create object of Class // to reflect the Dog class forName(“Dog”);.
