What is the best way to compare several javabean properties?

Question

I need to compare dozens of fields in two objects (instances of the same class), and do some logging and updating in case there are differences. Meta code could look somethi

Answer 1

Use Annotations.

If you mark the fields that you need to compare (no matter if they are private, you still don't lose the encapsulation, and then get those fields and compare them. It could be as follows:

In the Class that need to be compared:

@ComparableField 
private String field1;

@ComparableField
private String field2;

private String field_nocomparable;

And in the external class:

public  void compare(T t, T t2) throws IllegalArgumentException,
                                          IllegalAccessException {
    Field[] fields = t.getClass().getDeclaredFields();
    if (fields != null) {
        for (Field field : fields) {
            if (field.isAnnotationPresent(ComparableField.class)) {
                field.setAccessible(true);
                if ( (field.get(t)).equals(field.get(t2)) )
                    System.out.println("equals");
                field.setAccessible(false);
            }
        }
    }
}

The code is not tested, but let me know if helps.