The fact that clone is protected is extremely dubious – as is the fact that the clone method is not declared in the Cloneable interface. It makes the method pretty useless for taking copies of data because you cannot say: if(a instanceof Cloneable) { copy = ((Cloneable) a).clone(); } I think that the design of … Read more
Git This answer includes GitHub as many folks have asked about that too. Local repositories Git (locally) has a directory (.git) which you commit your files to and this is your ‘local repository’. This is different from systems like SVN where you add and commit to the remote repository immediately. Git stores each version of … Read more
Clone is broken, so dont use it. THE CLONE METHOD of the Object class is a somewhat magical method that does what no pure Java method could ever do: It produces an identical copy of its object. It has been present in the primordial Object superclass since the Beta-release days of the Java compiler*; and … Read more
You could add it as an extension method: public static T[] SubArray<T>(this T[] data, int index, int length) { T[] result = new T[length]; Array.Copy(data, index, result, 0, length); return result; } static void Main() { int[] data = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; int[] sub = data.SubArray(3, … Read more
Do you absolutely have to use clone? Most people agree that Java’s clone is broken. Josh Bloch on Design – Copy Constructor versus Cloning If you’ve read the item about cloning in my book, especially if you read between the lines, you will know that I think clone is deeply broken. […] It’s a shame … Read more
For deep cloning (clones the entire object hierarchy): commons-lang SerializationUtils – using serialization – if all classes are in your control and you can force implementing Serializable. Java Deep Cloning Library – using reflection – in cases when the classes or the objects you want to clone are out of your control (a 3rd party … Read more
If your elements are value types, then you can just do: List<YourType> newList = new List<YourType>(oldList); However, if they are reference types and you want a deep copy (assuming your elements properly implement ICloneable), you could do something like this: List<ICloneable> oldList = new List<ICloneable>(); List<ICloneable> newList = new List<ICloneable>(oldList.Count); oldList.ForEach((item) => { newList.Add((ICloneable)item.Clone()); }); … Read more
A safe way is to serialize the object, then deserialize. This ensures everything is a brand new reference. Here’s an article about how to do this efficiently. Caveats: It’s possible for classes to override serialization such that new instances are not created, e.g. for singletons. Also this of course doesn’t work if your classes aren’t … Read more
You will need to iterate on the items, and clone them one by one, putting the clones in your result array as you go. public static List<Dog> cloneList(List<Dog> list) { List<Dog> clone = new ArrayList<Dog>(list.size()); for (Dog item : list) clone.add(item.clone()); return clone; } For that to work, obviously, you will have to get your … Read more
Create a copy constructor: class DummyBean { private String dummy; public DummyBean(DummyBean another) { this.dummy = another.dummy; // you can access } } Every object has also a clone method which can be used to copy the object, but don’t use it. It’s way too easy to create a class and do improper clone method. … Read more