java - Reflection and constructors with interface argument -

i'm trying modify private field inside class, has constructor taking interface argument. having trouble instantiating such class (it throws java.lang.illegalargumentexception: wrong number of arguments). code stripped important details follows:

here reflection code inject different boolean value (unique field true default want false there):

private void modifysitepatterns() {      try {          thread thread = thread.currentthread();         classloader classloader = thread.getcontextclassloader();         class<?> classtomodify = class.forname(                 "dr.evolution.alignment.sitepatterns", true, classloader);         constructor<?>[] constructors = classtomodify                 .getdeclaredconstructors();         field[] fields = classtomodify.getdeclaredfields();          object classobj = constructors[0].newinstance(new object[] {}); //this throws exception          (int = 0; < fields.length; i++) {             if (fields[i].getname() == "unique") {                 system.out.println(i);                 fields[i].setaccessible(true);                 fields[i].set(classobj, false);              }         }      } catch (exception e) {         e.printstacktrace();     }  }// end: modifysitepatterns() 

here class i'm trying modify:

public class sitepatterns implements sitelist, dr.util.xhtmlable {  //omitted  private boolean unique = true;   public sitepatterns(alignment alignment) {// constructor 0     this(alignment, null, 0, 0, 1);    }  }    

and argument giving me trouble:

public interface alignment extends sequencelist, sitelist {     //omitted  public abstract class abstract implements alignment {  }  //omitted  } 

how should proceed passing fake argument instance of constructor?

you have no concrete implementation have shown us. not know how expect without concrete implementation of alignment.

//anonymous implementation object classobj = constructors[0].newinstance(new alignment() {     //alignment implementation... });  //or concrete implementation object classobj = constructors[0].newinstance(new alignmentimpl());