[JAVA] creating instance of the class

[temp temp <mi...@yahoo.com>]

    I want to  create  instance of a class  using object.getClass().new Instance()   but  this object constructor needs another object  so how can I do this ?
       
       
      Suppose I  have a class
       
      DefaultMetaInfoHandler   default=new DefaultMetaInfo(“test”);
       
      Can I  create instance of this class using  default.getClass().newInstance()
  
  If I have to create how ?
  
  Thanks
  Miro
  
    
 
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Re: [JAVA] creating instance of the class

[Niall Pemberton <ni...@gmail.com>]

On 2/9/07, temp temp <mi...@yahoo.com> wrote:
>     I want to  create  instance of a class  using object.getClass().new Instance()   but  this object constructor needs another object  so how can I do this ?
>
>
>       Suppose I  have a class
>
>       DefaultMetaInfoHandler   default=new DefaultMetaInfo("test");
>
>       Can I  create instance of this class using  default.getClass().newInstance()

You can't - you have to get hold of the constructor that has the
single argument and invoked it. So using your example - a constructor
that takes a single String parameter:

   Class clazz = DefaultMetaInfo.class;
   Classs[] paramTypes = new Class[] {String.class};

   // Get the constructor
   Constructor ctor = clazz.getConstructor(paramTypes);

    // Create a new instance
    Object[] args = new Object[] {"test"};
    DefaultMetaInfoHandler default =
(DefaultMetaInfoHandler)ctor.newInstance(args)

BeanUtils has convenience methods to do this - including one for a
constructor that takes a single argument:

   http://tinyurl.com/2hgkrm

So using BeanUtils al you need to do is:

   DefaultMetaInfoHandler default = (DefaultMetaInfoHandler)
               ConstructorUtils.invokeConstructor(DefaultMetaInfo.class,
"test");

Niall

>   If I have to create how ?
>
>   Thanks
>   Miro

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