Use try-with-resources in Spring 5 documentations

[pashazadeh]

Spring 5 supports JDK 8+, so it is much better to change the sample codes to Java 7 try-with-resources instead of old fashion style.

For example in 4.4.2. Implementing DAOs Based on JPA: EntityManagerFactory and EntityManager there exists following code

EntityManager em = this.emf.createEntityManager();
try {
    Query query = em.createQuery("from Product as p where p.category = ?1");
    query.setParameter(1, category);
    return query.getResultList();
} finally {
    if (em != null) {
        em.close();
    }
}

which could be replaced with

try(EntityManager em = this.emf.createEntityManager()) {
    Query query = em.createQuery("from Product as p where p.category = ?1");
    query.setParameter(1, category);
    return query.getResultList();
}

The same thing applies to OXM samples, and many more.