p.65

Test (int j, double y) {
  i = j;
  double x = y;
}

should be

Test (int j, double y) {
  i = j;
  x = y;
}

p.107

void double aMethod (Shape[] shapes)

should be

void aMethod (Shape[] shapes)

In the Complex class for complex numbers, discussed in Chapter 4 of the book and here in Chapter 4: Tech: Improved Complex Number Classs, the instance variables should be declared "public" so that classes in other packages can access these variables directly.

p.125

public class Complex {

  public double fReal;
  public double fImg;

   ...