Correct equals and hashCode

EqualsAndHashCode.java

//from http://developer.android.com/reference/java/lang/Object.html

// Use @Override to avoid accidental overloading.
   @Override public boolean equals(Object o) {
     // Return true if the objects are identical.
     // (This is just an optimization, not required for correctness.)
     if (this == o) {
       return true;
     }

     // Return false if the other object has the wrong type.
     // This type may be an interface depending on the interface's specification.
     if (!(o instanceof MyType)) {
       return false;
     }

     // Cast to the appropriate type.
     // This will succeed because of the instanceof, and lets us access private fields.
     MyType lhs = (MyType) o;

     // Check each field. Primitive fields, reference fields, and nullable reference
     // fields are all treated differently.
     return primitiveField == lhs.primitiveField &&
             referenceField.equals(lhs.referenceField) &&
             (nullableField == null ? lhs.nullableField == null
                                    : nullableField.equals(lhs.nullableField));
   }

   @Override public int hashCode() {
     // Start with a non-zero constant.
     int result = 17;

     // Include a hash for each field.
     result = 31 * result + (booleanField ? 1 : 0);

     result = 31 * result + byteField;
     result = 31 * result + charField;
     result = 31 * result + shortField;
     result = 31 * result + intField;

     result = 31 * result + (int) (longField ^ (longField >>> 32));

     result = 31 * result + Float.floatToIntBits(floatField);

     long doubleFieldBits = Double.doubleToLongBits(doubleField);
     result = 31 * result + (int) (doubleFieldBits ^ (doubleFieldBits >>> 32));

     result = 31 * result + Arrays.hashCode(arrayField);

     result = 31 * result + referenceField.hashCode();
     result = 31 * result +
         (nullableReferenceField == null ? 0
                                         : nullableReferenceField.hashCode());

     return result;
   }