NullPointerException when calling methods on DAO that is not attached to a Configuration

[lukaseder]

When users instantiate a generated DAOImpl class without a Configuration, the DAO doesn't really work. The intent is for the Configuration to be set later using DAO.setConfiguration(), but users might forget this. This will then produce a very unspecific NullPointerException in random DAO operations, see e.g. #9489.

Caused by: java.lang.NullPointerException
    at org.jooq.impl.DAOImpl.records(DAOImpl.java:421)
    at org.jooq.impl.DAOImpl.insert(DAOImpl.java:176)
    at org.jooq.impl.DAOImpl.insert(DAOImpl.java:152)

We should throw a DetachedException instead, which is much more specific and allows for helping users debug their DAO misconfiguration.

Additionally, we could think of deprecating the setConfiguration() method and the constructors that do not accept a Configuration as most people will be able to initialise their DAO instances eagerly, e.g. using DI.

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See also: #9489