Creating object of a Class variable

Question

I have a Class object, clazz. I want to make the object of that type class.

i.e. Class clazz = MTable.getClass(tableName);

The variable clazz may be of type MOrder.class, MInventory.class, or MSalary.class. Now I want to make the object of MOrder for an instance. Without comparing the clazz with MOrder.class, how can I create object of MOrder. Is Java providing any such mechanism?

Update:

I tried this:

Class<? extends DocAction> clazz = (Class<? extends DocAction>) MTable.getClass(re.tableName);
        DocAction instance = null;
        try {
                instance = clazz.newInstance();
        } catch (InstantiationException e1) {
            e1.printStackTrace();
        } catch (IllegalAccessException e1) {
            e1.printStackTrace();
        }

But an exception is thrown:

java.lang.InstantiationException: org.compiere.model.MOrder

Answer 1

Object object = clazz.newInstance();

would create the instance based on the value of clazz.

If you want to store the object in a MOrder variable, you have to check its type first :

MOrder order = null;
if (object instanceof MOrder) {
    order = (MOrder) order;
}

You can't avoid the testing of the type, since as you said, clazz may contain different Class instances.

If all of your classes implement DocAction interface, you can do the following :

Class<? extends DocAction> clazz = ...
DocAction instance = clazz.newInstace();

This would at least give you a reference of the type of the interface. You would still need to check the specific type if you want to store the instance in a more specific variable.

Answer 2

Try:

Object object = clazz.newInstance()

Answer 3

@Saj, the Class object is not inherited by your classes, so MOrder.class or MInventory.class can't be type of Class object. All object inherits from Object class, and even Class object inherits from Object class. So, your logic seems incorrect. Think in terms other way to know which type of Object to create.