These classes provide various implementations of the StockPrice API.

To compile these classes, you must have a JPA implementation. In your
environment, please set JAVAX_PERSISTENCE to the path to the jar file
containing the JPA API classes, e.g.
export JAVA_PERSISTENCE=/path_to/javax.persistence.jar

For examples that require Eclipselink-specific functionality, set
ECLIPSELINK_JAR to the path of the eclipselink implementation, e.g.
export ECLIPSELINK_JAR=/path_to/eclipselink.jar

There are several implementations of the stock price API, discussed mostly
in Chapter 11, as the implementation differences affect JPA. The choice of
those implementations is selected via -Dimpl value passed to the ant
comandline:
    -Dimpl=LazyLazyImpl (both relationships are annotated lazy)
    -Dimpl=EagerLazyImpl (the OneToMany stock->options relationship is eager)
    -Dimpl=EagerEagerImpl (both relationships are eager)
    -Dimpl=LazyEagerImpl (the ManyToOne options->stock relationship is eager)
For tests with the mock entity manager, use LazyLazyImpl, which is the
default.