AbstractNode { public boolean isNull() { return node instanceof NullNode; } AbstractNode(JsonNode node); @Nonnull List<N> getArrayValues(); @Nonnull Map<String, N> getObjectValues(); @Nonnull N getObject(@Nonnull String fieldName); N getObject(@Nonnull String fieldName, @Nullable N def); N getArray(@Nonnull String fieldName); N getArray(@Nonnull String fieldName, @Nullable N def); int getAsInt(@Nonnull String fieldName); int getAsInt(@Nonnull String fieldName, int def); BigInteger getAsBigInt(@Nonnull String fieldName); BigInteger getAsBigInt(@Nonnull String fieldName, BigInteger def); long getAsLong(@Nonnull String fieldName); boolean getAsBoolean(@Nonnull String fieldName); Boolean getAsBoolean(@Nonnull String fieldName, @Nullable Boolean def); @Nonnull String getAsString(@Nonnull String fieldName); String getAsString(@Nonnull String fieldName, @Nullable String def); @Nonnull String getAsString(); boolean isNull(); @Override String toString(); @Override boolean equals(Object obj); @Override int hashCode();  }
@Test public void isNull() { AbstractNode<N> node = parentWithChildString("A"); assertThat(node.getObjectValues().get("child").isNull()).isFalse(); node = parentWithChildNull(); assertThat(node.getObjectValues().get("child").isNull()).isTrue(); }