null references are a problem when: - null is a valid member of every type - there's no way to constrain a reference to only non-null members of the referenced

null references are a problem when: - null is a valid member of every type - there's no way to constrain a reference to only non-null members of the referenced type - the compiler allows dereferencing values of a nullable type Weirdly, all three are true of C, C++ and Java.