Nullpointerexception throws when inserting entity using Auto-generated Classendpoint insert method

Question

I am confused to using auto-generated endpoint class. I want to use generated endpoint to insert new object into datastore. But, an exception is throwing.

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Answer 1

I had exactly the same problem. I will present the way I worked around it.

Original auto-generated Endpoints class relevant code:

private boolean containsFoo(Foo foo) {
    EntityManager mgr = getEntityManager(); 
    boolean contains = true;
    try {
        Foo item = mgr.find(Foo.class, foo.getID());
        if (item == null) {
            contains = false;
        }
    } finally {
        mgr.close();
    }
    return contains;
}

Changed relevant code to include a null check for the entity object that is passed as an argument.

private boolean containsFoo(Foo foo) {
    EntityManager mgr = getEntityManager(); 
    boolean contains = true;
    try {
        // If no ID was set, the entity doesn't exist yet.
        if(foo.getID() == null)
            return false;
        Foo item = mgr.find(Foo.class, foo.getID());
        if (item == null) {
            contains = false;
        }
    } finally {
        mgr.close();
    }
    return contains;
}

This way it will work as supposed, although I'm confident that more experienced answers and explanations will appear.