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new 7c2d71cdfc31 [SPARK-58620][DOC][EXAMPLE] Fix incorrect comments and
stale usage docs in the custom receiver examples
7c2d71cdfc31 is described below
commit 7c2d71cdfc31e8ece7fd0d2f577185d9b483da4f
Author: Uros Bojanic <[email protected]>
AuthorDate: Fri Aug 7 10:10:01 2026 +0000
[SPARK-58620][DOC][EXAMPLE] Fix incorrect comments and stale usage docs in
the custom receiver examples
### What changes were proposed in this pull request?
Fixes documentation defects in the custom receiver examples:
1. `JavaCustomReceiver` documents a `<master>` argument the example does
not accept. The class comment is corrected to `Usage: JavaCustomReceiver
<hostname> <port>` and the stale `<master>` explanation is dropped. The
`<hostname>`/`<port>` line, which had no verb, is reworded to "describe the TCP
server ...".
2. The `onStop()` comment described the loop continuation condition instead
of the stop condition. Corrected to "is designed to stop by itself when
`isStopped()` returns true" in `JavaCustomReceiver.java`,
`CustomReceiver.scala`, and both snippets in
`docs/streaming-custom-receivers.md`.
3. `Received bytes is interpreted as` becomes `are` in
`JavaCustomReceiver.java`.
### Why are the changes needed?
Each defect is verifiable against the code in the same file:
- `main()` gates on `args.length < 2` and reads only `args[0]` as hostname
and `args[1]` as port; `SparkConf` is built with `setAppName` only, and
`setMaster` has never appeared in this file. The in-code `System.err.println`
already prints the two-argument usage, so only the class comment disagreed. The
stale text is a leftover of SPARK-1826, which removed the positional master
argument but left the comment block partly updated. This is the last remaining
`<master>` usage text under ` [...]
- The receive loop is `while (!isStopped() && ...)` in both the Java and
Scala examples, so the thread exits when `isStopped()` returns **true**. The
old comment stated the opposite, and also lacked a conjunction. The docs page
hand-inlines these snippets rather than using `include_example`, so it had
drifted the same way and is fixed alongside.
- "Received bytes" is plural. SPARK-15645 fixed this in
`CustomReceiver.scala` but missed the Java counterpart.
The `onStop()` fix is applied to all four occurrences so the Java example,
its Scala twin, and the docs snippets stay consistent.
### Does this PR introduce _any_ user-facing change?
No. Comments, example usage text, and documentation snippets only.
### How was this patch tested?
No functional change; nothing executable is modified. The corrected
statements were each checked against the surrounding code (argument parsing and
the `while (!isStopped())` loop).
### Was this patch authored or co-authored using generative AI tooling?
Generated-by: Claude Code (Opus 4.8)
Closes #57822 from uros-b/example-javacustomreceiver.
Authored-by: Uros Bojanic <[email protected]>
Signed-off-by: Uros Bojanic <[email protected]>
(cherry picked from commit 6caa418f7f85fdcf1b055de2b75459de3451783c)
Signed-off-by: Uros Bojanic <[email protected]>
---
docs/streaming-custom-receivers.md | 4 ++--
.../apache/spark/examples/streaming/JavaCustomReceiver.java | 10 +++++-----
.../org/apache/spark/examples/streaming/CustomReceiver.scala | 2 +-
3 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/docs/streaming-custom-receivers.md
b/docs/streaming-custom-receivers.md
index 11a52232510f..fdde5f0c0f8e 100644
--- a/docs/streaming-custom-receivers.md
+++ b/docs/streaming-custom-receivers.md
@@ -75,7 +75,7 @@ class CustomReceiver(host: String, port: Int)
def onStop() {
// There is nothing much to do as the thread calling receive()
- // is designed to stop by itself if isStopped() returns false
+ // is designed to stop by itself when isStopped() returns true
}
/** Create a socket connection and receive data until receiver is stopped */
@@ -137,7 +137,7 @@ public class JavaCustomReceiver extends Receiver<String> {
@Override
public void onStop() {
// There is nothing much to do as the thread calling receive()
- // is designed to stop by itself if isStopped() returns false
+ // is designed to stop by itself when isStopped() returns true
}
/** Create a socket connection and receive data until receiver is stopped */
diff --git
a/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java
b/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java
index f84a1978de1a..71fd665b6906 100644
---
a/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java
+++
b/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java
@@ -38,12 +38,12 @@ import java.util.Arrays;
import java.util.regex.Pattern;
/**
- * Custom Receiver that receives data over a socket. Received bytes is
interpreted as
+ * Custom Receiver that receives data over a socket. Received bytes are
interpreted as
* text and \n delimited lines are considered as records. They are then
counted and printed.
*
- * Usage: JavaCustomReceiver <master> <hostname> <port>
- * <master> is the Spark master URL. In local mode, <master> should be
'local[n]' with n > 1.
- * <hostname> and <port> of the TCP server that Spark Streaming would
connect to receive data.
+ * Usage: JavaCustomReceiver <hostname> <port>
+ * <hostname> and <port> describe the TCP server that Spark Streaming would
connect to receive
+ * data.
*
* To run this on your local machine, you need to first run a Netcat server
* `$ nc -lk 9999`
@@ -99,7 +99,7 @@ public class JavaCustomReceiver extends Receiver<String> {
@Override
public void onStop() {
// There is nothing much to do as the thread calling receive()
- // is designed to stop by itself isStopped() returns false
+ // is designed to stop by itself when isStopped() returns true
}
/** Create a socket connection and receive data until receiver is stopped */
diff --git
a/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
b/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
index 59d0641b62ce..d666c78605ff 100644
---
a/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
+++
b/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
@@ -73,7 +73,7 @@ class CustomReceiver(host: String, port: Int)
def onStop(): Unit = {
// There is nothing much to do as the thread calling receive()
- // is designed to stop by itself isStopped() returns false
+ // is designed to stop by itself when isStopped() returns true
}
/** Create a socket connection and receive data until receiver is stopped */
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