Key key = new MyExemptionMechanismSpi().new tmpKey("Proba", new byte[0]);
em.init(key);
// ExemptionMechanism doesn't check parameters
// it is a responsibility of ExemptionMechanismSpi
em.genExemptionBlob(null, 0);
em.genExemptionBlob(new byte[0], 0);
em.genExemptionBlob(new byte[10], -5);
}