Toarray ()

When we use the toarray () method, we usually encounter the problem of transformation without value, for example:

List widgetlist = new arraylist ();

 

String [] widgetarray = (string []) widgetlist. toarray ();

 

This transformation is obviously wrong. We know that the transformation in Java basically follows the problem of upward transformation. Here, if the above conversion method is used, the correct value cannot be converted in widgetarray. The correct method should be as follows:

List widgetlist = new arraylist ();

 

String [] widgetarray = new string [widgetlist. Size ()];

 

Widgetlist. toarray (widgetarray );

 

In fact, we can think of the toarray (New String [size]) method as copying all object [] to the new string [] array.