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Java reflection instantiate class by name code#

out.println( "Player Simple Name: " + player.getClass().getSimpleName()) Īt $1.run(URLClassLoader.java:202)Īt (Native Method)Īt (URLClassLoader.java:190)Īt (ClassLoader.java:306)Īt $AppClassLoader.loadClass(Launcher.java:301)Īt (ClassLoader.java:247)Īt 0(Native Method)Īt (Class.java:171)Īt .main(ClassExample.java:7)

out.println( "Player Class Name: " + player.getClass().getName()) step 1:- Load class with given input name as String Class<> obj Class.forName('CompleteClassNameincludingpackage') //like:- Class obj Class.

Let’s look at the example when using another class, this time let’s look at the Player class.

out.println( "Canonical Name: " + myString.getClass().getCanonicalName())

out.println( "Simple Name: " + myString.getClass().getSimpleName()) out.println( "Name: " + myString.getClass().getName()) In order to get the name of a object’s class by using the getName(), getSimpleName(), or getCanonicalName() methods. We can inspect any class and get it’s name using the getClass() method Getting the Class Name

getAnnotation, getAnnotations, getDeclaredAnnotations.

getMethod, getMethods, getDeclaredMethods.

getConstructor, getConstructors, getDeclaredConstructor, getDeclaredConstructors, getEnclosingConstructor.

Hence, if we change the variables of object x, that is reflected when we access the variables of objects y and z. But actually, after the creation of object x, variables y and z are pointed to object x as shown in the diagram. With it we will be able to determine the properties of a class and find all its fields, methods, interfaces, see if annotations are present, etc. In the main class, we instantiate the singleton class with 3 objects x, y, z by calling the static method getInstance().

Java reflection instantiate class by name code#

concept of reflection is used to code TestHarness.java, which takes the name of the Class Under Test (CUT) as its command line input. In later post, we will discuss in detail how we can use this Class class for reflection. TestHarness.java automatically tests classes by instantiating them, selecting methods of these instantiated objects randomly or using some criteria, invoking them, and using the returned values as input parameters to invoke other methods. According to the Javadocs, Class objects are constructed automatically by the Java Virtual Machine as classes are loaded and by calls to the defineClass method in the class loader. Actually, for every class that you use there is a Class object associated with it. Please check whether arguments are passed in commandline correctly.In Java, the classes in your source code are are instances of the class during runtime. Please check whether the folder structure mentioned in maintained. Please check whether the package mentioned in java file is same the package which contains the. If the invoked method prints any message, it will shown in console. The Test.java will write the report of test cases and its status in to output.txt Make sure that the folder structure mentioned in "Folder Hierarchy" is maintained Please unzip the folder and import project OOLE_HW1 in to eclipse. Here OOLE_HW_1 is package and cut is class name.

If you are using eclipse, please configure the the class name by following these stepsġ)In package explorer, Right click of Test.javaĤ)double click on the class Test under "Launch Configurations for 'Test.java'"Ħ)write 'OOLE_HW_1.cut' (without quotes) in Program Arguments. The main program in Test.java expects the name of the class( in the format of PackageName.ClassName), which is under test in command line arguments. The Test.java contains main method, which instantiates the class cut and invokes it's methods.Ģ)Inputs are read from input.txt file.It is present in the base folder OOLE_HW1.ģ)Results of the test cases are written in to output.txt, which is also present in base folder OOLE_HW1. It contains cut.java, which is the Class Under Test and Test.java, which is the Test Harness. 1)The src folder contains OOLE_HW_1 folder.