Copy object into another

Question

Is there a generic way to achieve copying an existing object into another?

Assume MyObj has an id and name fields. Like this:

MyObj myObj_1 = new MyObj(1, "Name 1");
MyObj myObj_2 = new MyObj(2, "Name 2");

Instead of

myObj_2.setName(myObj_1.getName()) // etc for each field

do something as following:

myObj_2.copyFrom(myObj_1)

so that they are different instances, but have equal properties.

Answer 1

The convention is to do this at construction time with a constructor that takes one parameter of its own type.

MyObj myObj_2 = new MyObj(myObj_1);

There is no Java convention to overwrite the existing properties of an object from another. This tends to go against the preference for immutable objects in Java (where properties are set at construction time unless there is a good reason not to).

Edit: regarding clone(), many engineers discourage this in modern Java because it has outdated syntax and other drawbacks. http://www.javapractices.com/topic/TopicAction.do?Id=71