Serializing a non-static
inner class will result in an attempt at serializing the outer class as well. If the outer class is actually
serializable, then the serialization will succeed but possibly write out far more data than was intended.
Making the inner class static
(i.e. "nested") avoids this problem, therefore inner classes should be static
if possible.
However, you should be aware that there are semantic differences between an inner class and a nested one:
static
) class can be instantiated independently of the outer class. public class Raspberry implements Serializable { // ... public class Drupelet implements Serializable { // Noncompliant; output may be too large // ... } }
public class Raspberry implements Serializable { // ... public static class Drupelet implements Serializable { // ... } }