There is no good reason to declare a field "public" and "static" without also declaring it "final". Most of the time this is a kludge to share a
state among several objects. But with this approach, any object can do whatever it wants with the shared state, such as setting it to
null
.
Noncompliant code example
public class Greeter {
public static Foo foo = new Foo();
...
}
Compliant solution
public class Greeter {
public static final Foo FOO = new Foo();
...
}