The following is a table outlining the default behaviour of JFixture. This applies if no customisations or custom builders have been added to the JFixture instance.

Data Type	Value/s
Boolean	Alternate between TRUE and FALSE
Number*	Random integer; range from [1-127], then [128-32766], etc
String	UUID**
UUID	UUID
Character	Random; 'a'-'z'
Date	Random; now +-2 years
Calendar	Gregorian, random date; now +-2 years
Primitives	Boxed equivilant
Array	Populated array***
Iterable, List	Populated ArrayList***
Map	Populated HashMap***
Set	Populated HashSet***
Queue	Populated ArrayDeque***
Enum	Shuffles values and cycles through them
Type/Class	Invokes smallest constructor
Abstract Class/Interface	Undefined****

*Supported Numbers are Byte, Short, Integer, Long, Float, Double, BigDecimal, BigInteger and their primitive versions where applicable

**Prefixed with field/property name where applicable

***All collection type objects are populated with 3 items by default

****For abstract classes/interfaces not covered by the default behaviour a SubTypeCustomisation could be used.

This is process involved in creating a type

1. Construct instance of requested type
   1. Priority given to constructors, ordered by ascending parameter count
   2. If that fails look for factory methods (public, static methods with return type assignable to declaring type), ordered by ascending parameter count
2. Create instances of all parameter types
3. Invoke construction method (constructor or factory method) with parameters values
4. Find all settable properties (getter, setter pairs with one argument in the setter)
   1. Create instance of parameter type
   2. Call the setter with the parameter instance
   3. Repeat for all settable properties
5. Find all settable fields (public, non-final, non-static)
   1. Create instance of field type
   2. Invoke set method on the field with the parameter instance
   3. Repeat for all settable fields
6. Return object

If a recursive call (Type Foo has property Bar which has property Foo) is identified JFixture will throw an exception with a detailed error message explaining which type caused the problem. You should redesign your classes to remove the cyclic dependency, or customise JFixture to prevent it resolving the problem area.