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Creating an Object When its Class Is Unknown Before Runtime

Creating an Object When its Class Is Unknown Before Runtime

If you are writing an application in which you don’t know the class of an object until runtime, then you cannot use the new operator to instantiate the object. This is because new does not take the name of class file as a parameter. In this situation, you have to use the newInstance method of class Class. The code snippet given below demonstrates the technique:

 Object object = null;try{ Class classDefinition = Class.forName(className); object = classDefinition.newInstance();}catch (InstantiationException e) {          System.out.println(e);      }catch (IllegalAccessException e) {          System.out.println(e);      }catch (ClassNotFoundException e) {          System.out.println(e);      }return object;

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Here, className is the fully qualified name of the desired class. For example: java.lang.Thread.

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