[
https://issues.apache.org/jira/browse/FLINK-10186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16601903#comment-16601903
]
ASF GitHub Bot commented on FLINK-10186:
----------------------------------------
zentol closed pull request #6591: [FLINK-10186] Fix FindBugs warnings: Random
object created and used o…
URL: https://github.com/apache/flink/pull/6591
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git
a/flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/io/BufferSpiller.java
b/flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/io/BufferSpiller.java
index 7a0be33be61..4b690d1f750 100644
---
a/flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/io/BufferSpiller.java
+++
b/flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/io/BufferSpiller.java
@@ -35,7 +35,7 @@
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
-import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicInteger;
/**
@@ -115,7 +115,7 @@ public BufferSpiller(IOManager ioManager, int pageSize)
throws IOException {
this.tempDir = tempDirs[DIRECTORY_INDEX.getAndIncrement() %
tempDirs.length];
byte[] rndBytes = new byte[32];
- new Random().nextBytes(rndBytes);
+ ThreadLocalRandom.current().nextBytes(rndBytes);
this.spillFilePrefix = StringUtils.byteToHexString(rndBytes) +
'.';
// prepare for first contents
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
> FindBugs warnings: Random object created and used only once
> -----------------------------------------------------------
>
> Key: FLINK-10186
> URL: https://issues.apache.org/jira/browse/FLINK-10186
> Project: Flink
> Issue Type: Bug
> Components: Streaming
> Reporter: Hiroaki Yoshida
> Priority: Major
> Labels: pull-request-available
>
> FindBugs-3.0.1 ([http://findbugs.sourceforge.net/]) reported a
> DMI_RANDOM_USED_ONLY_ONCE warning on master:
> {code:java}
> H B DMI: Random object created and used only once in new
> org.apache.flink.streaming.runtime.io.BufferSpiller(IOManager, int) At
> BufferSpiller.java:[line 118]
> {code}
> The description of the bug is as follows:
> {quote}*DMI: Random object created and used only once
> (DMI_RANDOM_USED_ONLY_ONCE)*
> This code creates a java.util.Random object, uses it to generate one random
> number, and then discards the Random object. This produces mediocre quality
> random numbers and is inefficient. If possible, rewrite the code so that the
> Random object is created once and saved, and each time a new random number is
> required invoke a method on the existing Random object to obtain it.
> If it is important that the generated Random numbers not be guessable, you
> must not create a new Random for each random number; the values are too
> easily guessable. You should strongly consider using a
> java.security.SecureRandom instead (and avoid allocating a new SecureRandom
> for each random number needed).
> [http://findbugs.sourceforge.net/bugDescriptions.html#DMI_RANDOM_USED_ONLY_ONCE]
> {quote}
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
