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HADOOP-13500. Synchronizing iteration of Configuration properties object (#3776) 

Signed-off-by: Akira Ajisaka <aajisaka@apache.org>
This commit is contained in:
Dhananjay Badaya 2021-12-17 21:37:38 +05:30 committed by GitHub
parent 2873606fc9
commit ebf569793b
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 41 additions and 4 deletions
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10
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
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@ -2696,11 +2696,13 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
// methods that allow non-strings to be put into configurations are removed, // methods that allow non-strings to be put into configurations are removed,
// we could replace properties with a Map<String,String> and get rid of this // we could replace properties with a Map<String,String> and get rid of this
// code. // code.
Map<String,String> result = new HashMap<String,String>(); Properties props = getProps();
for(Map.Entry<Object,Object> item: getProps().entrySet()) { Map<String, String> result = new HashMap<>();
if (item.getKey() instanceof String && synchronized (props) {
item.getValue() instanceof String) { for (Map.Entry<Object, Object> item : props.entrySet()) {
if (item.getKey() instanceof String && item.getValue() instanceof String) {
result.put((String) item.getKey(), (String) item.getValue()); result.put((String) item.getKey(), (String) item.getValue());
}
} }
} }
return result.entrySet().iterator(); return result.entrySet().iterator();

35
hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java
View File

@ -36,12 +36,14 @@ import java.nio.charset.StandardCharsets;
import java.util.ArrayList; import java.util.ArrayList;
import java.util.Arrays; import java.util.Arrays;
import java.util.Collection; import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.HashMap; import java.util.HashMap;
import java.util.HashSet; import java.util.HashSet;
import java.util.List; import java.util.List;
import java.util.Map; import java.util.Map;
import java.util.Random; import java.util.Random;
import java.util.Set; import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.regex.Pattern; import java.util.regex.Pattern;
import static java.util.concurrent.TimeUnit.*; import static java.util.concurrent.TimeUnit.*;
@ -2133,6 +2135,39 @@ public class TestConfiguration extends TestCase {
checkCDATA(os.toByteArray()); checkCDATA(os.toByteArray());
} }
@Test
public void testConcurrentModificationDuringIteration() throws InterruptedException {
final Configuration configuration = new Configuration();
new Thread(new Runnable() {
@Override
public void run() {
while (true) {
configuration.set(String.valueOf(Math.random()), String.valueOf(Math.random()));
}
}
}).start();
final AtomicBoolean exceptionOccurred = new AtomicBoolean(false);
new Thread(new Runnable() {
@Override
public void run() {
while (true) {
try {
configuration.iterator();
} catch (final ConcurrentModificationException e) {
exceptionOccurred.set(true);
break;
}
}
}
}).start();
Thread.sleep(1000); //give enough time for threads to run
assertFalse("ConcurrentModificationException occurred", exceptionOccurred.get());
}
private static Configuration checkCDATA(byte[] bytes) { private static Configuration checkCDATA(byte[] bytes) {
Configuration conf = new Configuration(false); Configuration conf = new Configuration(false);
conf.addResource(new ByteArrayInputStream(bytes)); conf.addResource(new ByteArrayInputStream(bytes));