#JAVA REFLECTION INVOKE METHOD CODE#

If this Class represents either the Object class, an interface, a primitive type, or void, then null is returned. GetSuperclass() method on a Class object returns the super class of the class. Check out Java Generics Tutorial to learn about generics and its wildcards. Notice that uses Generics, it helps frameworks in making sure that the Class retrieved is subclass of framework Base Class. GetCanonicalName() returns the canonical name of the underlying class. (twoDStringArray.getCanonicalName()) // prints (cDoubleArray.getCanonicalName()) //prints doubleĬlass twoDStringArray = String.class (cDouble.getCanonicalName()) // prints doubleĬlass cDoubleArray = Class.forName('[D') (booleanClass.getCanonicalName()) // prints boolean for primitive types, wrapper classes and arrays (concreteClass.getCanonicalName()) // prints

because ConcreteClass is not available at compile timeĬoncreteClass = Class.forName('') Eclipse auto completion of method names, hibernate, Struts2 etc. Spring dependency injection, Tomcat web container below method is used most of the times in frameworks like JUnit Get Class using reflectionĬlass concreteClass = ConcreteClass.class ĬoncreteClass = new ConcreteClass(5).getClass() Wrapper classes provide another static variable TYPE to get the class. For primitive types and arrays, we can use static variable class. We can get Class of an object using three methods - through static variable class, using getClass() method of object and (String full圜lassifiedClassName). Let’s look at some of the important refection methods for classes. Package class ConcreteClass extends BaseClass implements BaseInterface In this section, we will look into important methods of Class, for convenience, I am creating some classes and interfaces with inheritance hierarchy. For every type of object, JVM instantiates an immutable instance of that provides methods to examine the runtime properties of the object and create new objects, invoke its method and get/set object fields. is the entry point for all the reflection operations. Primitive types are - boolean, byte, short, int, long, char, float, and double. All the classes, enums, arrays are reference types and inherit from. In java, every object is either a primitive type or reference.

#JAVA REFLECTION INVOKE METHOD CODE#

High Maintenance - Reflection code is hard to understand and debug, also any issues with the code can’t be found at compile time because the classes might not be available, making it less flexible and hard to maintain.

This can be a serious security threat and cause your application to behave abnormally. Security Issues - Using reflection we can access part of code that we are not supposed to access, for example we can access private fields of a class and change it’s value.This can cause you application to fail at runtime because of security manager. Security Restrictions - Reflection requires runtime permissions that might not be available for system running under security manager.Poor Performance - Since java reflection resolve the types dynamically, it involves processing like scanning the classpath to find the class to load, causing slow performance.

We should not use reflection in normal programming where we already have access to the classes and interfaces because of following drawbacks. The list is endless and they all use java reflection because all these frameworks have no knowledge and access of user defined classes, interfaces, their methods etc. Eclipse auto completion of method names.Tomcat web container to forward the request to correct module by parsing their web.xml files and request URI.Spring - dependency injection, read more at Spring Dependency Injection.JUnit - uses reflection to parse annotation to get the test methods and then invoke it.Some of the frameworks that use java reflection are: Reflection in Java is a very powerful concept and it’s of little use in normal programming but it’s the backbone for most of the Java, J2EE frameworks. We can also use reflection to instantiate an object, invoke it’s methods, change field values. Using java reflection we can inspect a class, interface, enum, get their structure, methods and fields information at runtime even though class is not accessible at compile time. Reflection in Java is one of the advance topic of core java. Access all private fields of the class.Java Reflection provides ability to inspect and modify the runtime behavior of application.

Java reflection invoke method