In java, you can do this by using Reflection:
Reflection is commonly used by programs which require the ability to
examine or modify the runtime behavior of applications running in the
Java virtual machine.
For example:
try {
addObject(c.newInstance(),x,y);
} catch (InstantiationException | IllegalAccessException e) {
e.printStackTrace();
}
For more about reflection, you can read here.
Hope it helps.
solved Java: Creating an object, specified by a variable