Create new object using reflection?

Question

Given class Value :

public class Value {

    private int xVal1;
    private int xVal2; 
    private double pVal;


    // constructor of the Value class 

         


        

Answer 1

You need to locate the exact constructor for this. Class.newInstance() can only be used to call the nullary constructor. So write

final Value v = Value.class.getConstructor(
   int.class, int.class, double.class).newInstance(_xval1,_xval2,_pval);

Answer 2

The Class.newInstance() method can only invoke a no-arg constructor. If you want to create objects using reflection with parameterized constructor than you need to use Constructor.newInstance(). You can simply write

Constructor<Value> constructor = Value.class.getConstructor(int.class, int.class, double.class);
Value obj = constructor.newInstance(_xval1,_xval2,_pval);

For details you can read Creating objects through Reflection in Java with Example