diff --git a/arrow-json/src/writer/encoder.rs b/arrow-json/src/writer/encoder.rs
index f5c09b9da74..1e7b14ef3ae 100644
--- a/arrow-json/src/writer/encoder.rs
+++ b/arrow-json/src/writer/encoder.rs
@@ -166,7 +166,7 @@ fn make_encoder_impl<'a>(
 
             let encoder = StructArrayEncoder{
                 encoders,
-                nulls: array.nulls().clone(),
+                nulls: array.nulls(),
                 explicit_nulls: options.explicit_nulls,
             };
             Box::new(encoder) as _
@@ -332,7 +332,10 @@ struct PrimitiveEncoder<N: PrimitiveEncode> {
 }
 
 impl<N: PrimitiveEncode> PrimitiveEncoder<N> {
-    fn new<P: ArrowPrimitiveType<Native = N>>(array: &PrimitiveArray<P>, nulls: Option<NullBuffer>) -> Self {
+    fn new<P: ArrowPrimitiveType<Native = N>>(
+        array: &PrimitiveArray<P>,
+        nulls: Option<NullBuffer>,
+    ) -> Self {
         Self {
             values: array.values().clone(),
             nulls,
@@ -418,7 +421,7 @@ impl<'a, O: OffsetSizeTrait> ListEncoder<'a, O> {
         options: &EncoderOptions,
     ) -> Result<Self, ArrowError> {
         let nulls = array.logical_nulls();
-        let encoder= make_encoder_impl(array.values().as_ref(), options)?;
+        let encoder = make_encoder_impl(array.values().as_ref(), options)?;
         Ok(Self {
             offsets: array.offsets().clone(),
             encoder,
@@ -537,20 +540,15 @@ impl<K: ArrowDictionaryKeyType> Encoder for DictionaryEncoder<'_, K> {
     }
 }
 
-
-
 /// A newtype wrapper around [`ArrayFormatter`] to keep our usage of it private and not implement `Encoder` for the public type
 struct JsonArrayFormatter<'a> {
     formatter: ArrayFormatter<'a>,
     nulls: Option<&'a NullBuffer>,
 }
 
-impl <'a> JsonArrayFormatter<'a> {
+impl<'a> JsonArrayFormatter<'a> {
     fn new(formatter: ArrayFormatter<'a>, nulls: Option<&'a NullBuffer>) -> Self {
-        Self {
-            formatter,
-            nulls,
-        }
+        Self { formatter, nulls }
     }
 }
 
diff --git a/arrow-json/src/writer/mod.rs b/arrow-json/src/writer/mod.rs
index 48e6492ec51..fd86b9ca665 100644
--- a/arrow-json/src/writer/mod.rs
+++ b/arrow-json/src/writer/mod.rs
@@ -1986,7 +1986,9 @@ mod tests {
                 match &self.array[idx] {
                     None => out.extend_from_slice(b"null"),
                     Some(UnionValue::Int32(v)) => out.extend_from_slice(v.to_string().as_bytes()),
-                    Some(UnionValue::String(v)) => out.extend_from_slice(format!("\"{}\"", v).as_bytes()),
+                    Some(UnionValue::String(v)) => {
+                        out.extend_from_slice(format!("\"{}\"", v).as_bytes())
+                    }
                 }
             }
 
@@ -2023,35 +2025,28 @@ mod tests {
                         _ => return Ok(None),
                     }
                 }
-                let (_, type_ids, _, buffers) = array
-                    .as_union()
-                    .clone()
-                    .into_parts();
+                let (_, type_ids, _, buffers) = array.as_union().clone().into_parts();
                 let mut values = Vec::with_capacity(type_ids.len());
                 for idx in 0..type_ids.len() {
                     let type_id = type_ids[idx];
                     let field = &fields[type_id as usize];
                     let value = match field.data_type() {
                         DataType::Null => None,
-                        DataType::Int32 => Some(
-                            UnionValue::Int32(
-                                buffers[type_id as usize]
-                                    .as_any()
-                                    .downcast_ref::<Int32Array>()
-                                    .unwrap()
-                                    .value(idx),
-                            )
-                        ),
-                        DataType::Utf8 => Some(
-                            UnionValue::String(
-                                buffers[type_id as usize]
-                                    .as_any()
-                                    .downcast_ref::<StringArray>()
-                                    .unwrap()
-                                    .value(idx)
-                                    .to_string(),
-                            )
-                        ),
+                        DataType::Int32 => Some(UnionValue::Int32(
+                            buffers[type_id as usize]
+                                .as_any()
+                                .downcast_ref::<Int32Array>()
+                                .unwrap()
+                                .value(idx),
+                        )),
+                        DataType::Utf8 => Some(UnionValue::String(
+                            buffers[type_id as usize]
+                                .as_any()
+                                .downcast_ref::<StringArray>()
+                                .unwrap()
+                                .value(idx)
+                                .to_string(),
+                        )),
                         _ => unreachable!(),
                     };
                     values.push(value);
@@ -2238,8 +2233,7 @@ mod tests {
                 &self,
                 array: &'a dyn Array,
                 _options: &EncoderOptions,
-            ) -> Result<Option<Box<dyn Encoder + 'a>>, ArrowError>
-            {
+            ) -> Result<Option<Box<dyn Encoder + 'a>>, ArrowError> {
                 match array.data_type() {
                     DataType::Binary => {
                         let array = array.as_any().downcast_ref::<BinaryArray>().unwrap();