The Clone method of Java

Recently I encountered a bit of a problem writing the squared method in the Hugenumber class. The problem was found to be not cloned on the object.

The following is a summary of the several points on cloning;

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One of the advantages of the Java language is that it cancels the concept of pointers, but it also causes many programmers to ignore objects and references in programming often.

The difference, especially the first C, C + + after the Java programmer. And because Java cannot solve object duplication by simply assigning a value

, the Clone () method is often used to replicate objects during the development process. For example, a function parameter type is a custom class

, this is a reference pass instead of a value pass . Here is a small example:

 Public classTestclone { Public voidChangea (A a) {A.name= "B"; }     Public voidChangint (inti) {i=i*2+100; }        /**     * @paramargs*/     Public Static voidMain (string[] args) {//TODO auto-generated Method StubTestclone test=NewTestclone (); A A=NewA (); A.name= "a"; System.out.println ("Before Change:a.name=" +a.name);        Test.changea (a); System.out.println ("After Change:a.name=" +a.name); intI=1; System.out.println ("Before change:i=" +i);        Test.changint (i); System.out.println ("After change:i=" +i); }}

When the Class A member variable type is the basic type of Java (plus string type), it is possible to implement the simple clone (called Shadow clone) as above.

However, if a class A member variable is an array or complex type, deep clone must be implemented.

 Public Object Clone () {        null;         Try {            super. Clone ();            O.name= (string[]) name.clone (); // It 's very simple, actually. ^_^        Catch (clonenotsupportedexception e) {            e.printstacktrace ();        }         return o;    }

Otherwise the clone is actually the address of the original object.

The Clone method of Java