[java] Is there a way to instantiate a class by name in Java?

I was looking as the question : Instantiate a class from its string name which describes how to instantiate a class when having its name. Is there a way to do it in Java? I will have the package name and class name and I need to be able to create an object having that particular name.

Class.forName("ClassName") will solve your purpose.

Class class1 = Class.forName(ClassName);
Object object1 = class1.newInstance();

use Class.forName("String name of class").newInstance();

Class.forName("A").newInstance();

This will cause class named A initialized.

something like this should work...

String name = "Test2";//Name of the class
        Class myClass = Class.forName(name);
        Object o = myClass.newInstance();

String str = (String)Class.forName("java.lang.String").newInstance();

Use java reflection

Creating New Objects There is no equivalent to method invocation for constructors, because invoking a constructor is equivalent to creating a new object (to be the most precise, creating a new object involves both memory allocation and object construction). So the nearest equivalent to the previous example is to say:

import java.lang.reflect.*;

   public class constructor2 {
      public constructor2()
      {
      }

      public constructor2(int a, int b)
      {
         System.out.println(
           "a = " + a + " b = " + b);
      }

      public static void main(String args[])
      {
         try {
           Class cls = Class.forName("constructor2");
           Class partypes[] = new Class[2];
            partypes[0] = Integer.TYPE;
            partypes[1] = Integer.TYPE;
            Constructor ct 
              = cls.getConstructor(partypes);
            Object arglist[] = new Object[2];
            arglist[0] = new Integer(37);
            arglist[1] = new Integer(47);
            Object retobj = ct.newInstance(arglist);
         }
         catch (Throwable e) {
            System.err.println(e);
         }
      }
   }

which finds a constructor that handles the specified parameter types and invokes it, to create a new instance of the object. The value of this approach is that it's purely dynamic, with constructor lookup and invocation at execution time, rather than at compilation time.

Using newInstance() directly is deprecated as of Java 8. You need to use Class.getDeclaredConstructor(...).newInstance(...) with the corresponding exceptions.

To make it easier to get the fully qualified name of a class in order to create an instance using Class.forName(...), one could use the Class.getName() method. Something like:

class ObjectMaker {
    // Constructor, fields, initialization, etc...
    public Object makeObject(Class<?> clazz) {
        Object o = null;

        try {
            o = Class.forName(clazz.getName()).newInstance();
        } catch (ClassNotFoundException e) {
            // There may be other exceptions to throw here, 
            // but I'm writing this from memory.
            e.printStackTrace();
        }

        return o;
    }
}

Then you can cast the object you get back to whatever class you pass to makeObject(...):

Data d = (Data) objectMaker.makeObject(Data.class);

MyClass myInstance = (MyClass) Class.forName("MyClass").newInstance();