KAFKA-13197: fix GlobalKTable join/left-join semantics documentation. (#14187)

Reviewers: Matthias J. Sax <matthias@confluent.io>

streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java

@@ -2805,10 +2805,8 @@ public interface KStream<K, V> {
      * For each {@code KStream} record that finds a corresponding record in {@link GlobalKTable} the provided
      * {@link ValueJoiner} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as the key of this {@code KStream}.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, no output record will be added to the
-     * resulting {@code KStream}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      *
      * @param globalTable    the {@link GlobalKTable} to be joined with this stream
      * @param keySelector    instance of {@link KeyValueMapper} used to map from the (key, value) of this stream
@@ -2839,10 +2837,8 @@ public interface KStream<K, V> {
      * {@link ValueJoinerWithKey} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as the key of this {@code KStream}.
      * Note that the key is read-only and should not be modified, as this can lead to undefined behaviour.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, no output record will be added to the
-     * resulting {@code KStream}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      *
      * @param globalTable    the {@link GlobalKTable} to be joined with this stream
      * @param keySelector    instance of {@link KeyValueMapper} used to map from the (key, value) of this stream
@@ -2872,10 +2868,8 @@ public interface KStream<K, V> {
      * For each {@code KStream} record that finds a corresponding record in {@link GlobalKTable} the provided
      * {@link ValueJoiner} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as the key of this {@code KStream}.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, no output record will be added to the
-     * resulting {@code KStream}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      *
      * @param globalTable    the {@link GlobalKTable} to be joined with this stream
      * @param keySelector    instance of {@link KeyValueMapper} used to map from the (key, value) of this stream
@@ -2908,10 +2902,8 @@ public interface KStream<K, V> {
      * {@link ValueJoinerWithKey} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as the key of this {@code KStream}.
      * Note that the key is read-only and should not be modified, as this can lead to undefined behaviour.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, no output record will be added to the
-     * resulting {@code KStream}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      *
      * @param globalTable    the {@link GlobalKTable} to be joined with this stream
      * @param keySelector    instance of {@link KeyValueMapper} used to map from the (key, value) of this stream
@@ -2945,10 +2937,8 @@ public interface KStream<K, V> {
      * For each {@code KStream} record whether or not it finds a corresponding record in {@link GlobalKTable} the
      * provided {@link ValueJoiner} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as this {@code KStream}.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, a {@code null} value will be
-     * provided to {@link ValueJoiner}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      * If no {@link GlobalKTable} record was found during lookup, a {@code null} value will be provided to
      * {@link ValueJoiner}.
      *
@@ -2983,10 +2973,8 @@ public interface KStream<K, V> {
      * provided {@link ValueJoinerWithKey} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as this {@code KStream}.
      * Note that the key is read-only and should not be modified, as this can lead to undefined behaviour.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, a {@code null} value will be
-     * provided to {@link ValueJoinerWithKey}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      * If no {@link GlobalKTable} record was found during lookup, a {@code null} value will be provided to
      * {@link ValueJoiner}.
      *
@@ -3020,10 +3008,8 @@ public interface KStream<K, V> {
      * For each {@code KStream} record whether or not it finds a corresponding record in {@link GlobalKTable} the
      * provided {@link ValueJoiner} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as this {@code KStream}.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, a {@code null} value will be
-     * provided to {@link ValueJoiner}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      * If no {@link GlobalKTable} record was found during lookup, a {@code null} value will be provided to
      * {@link ValueJoiner}.
      *
@@ -3059,10 +3045,8 @@ public interface KStream<K, V> {
      * For each {@code KStream} record whether or not it finds a corresponding record in {@link GlobalKTable} the
      * provided {@link ValueJoinerWithKey} will be called to compute a value (with arbitrary type) for the result record.
      * The key of the result record is the same as this {@code KStream}.
-     * If a {@code KStream} input record key or value is {@code null} the record will not be included in the join
-     * operation and thus no output record will be added to the resulting {@code KStream}.
-     * If {@code keyValueMapper} returns {@code null} implying no match exists, a {@code null} value will be
-     * provided to {@link ValueJoinerWithKey}.
+     * If a {@code KStream} input value is {@code null} or if {@code keyValueMapper} returns {@code null} the record
+     * will not be included in the join operation and thus no output record will be added to the resulting {@code KStream}.
      * If no {@link GlobalKTable} record was found during lookup, a {@code null} value will be provided to
      * {@link ValueJoinerWithKey}.
      *