RandomNumberGen

	double x1 = 1.0, x2 = 10.0;  //or float x1 = 1.0f, x2 =2.0f
	double f = Math.random()/Math.nextDown(1.0);
	double x = x1*(1.0 - f) + x2*f;
	
	//test code
	
	    int c = 0;
    while(c< 20)  {
    float x1 = 1.0f, x2 = 10.0f;
    double f  = Math.random() / Math.nextDown( 1.0 );
    double x  = x1 * ( 1.0 - f ) + x2 * f;
    System.out.printf( "%d) %f\n" , (c + 1),  x );
    c++;
  }