Vladimir Zhilin created DBUTILS-140:
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Summary: Thread safety problem in BeanProcessor
Key: DBUTILS-140
URL: https://issues.apache.org/jira/browse/DBUTILS-140
Project: Commons DbUtils
Issue Type: Bug
Affects Versions: 1.7
Environment: jdk1.8.0_171
Reporter: Vladimir Zhilin
Attachments: dbutils-bug-test.zip
Sometimes Exception occurs when method QueryRunner.query() is called with
BeanHandler.
{code:java}
// works fine with N = 1
int N = 8;
ExecutorService execs = Executors.newFixedThreadPool(N);
Runnable task = () -> {
try {
Data bean = runner.query("select id from test_table", new
BeanHandler<Data>(Data.class));
System.out.println("result: " + bean);
} catch (Exception e) {
e.printStackTrace();
}
};
for (int i = 0; i < N; i++) {
execs.submit(task);
}
{code}
Full code is attached: dbutils-bug-test.zip
Exception
{code:java}
java.util.NoSuchElementException
at sun.misc.CompoundEnumeration.nextElement(CompoundEnumeration.java:59)
at java.util.ServiceLoader$LazyIterator.hasNextService(ServiceLoader.java:357)
at java.util.ServiceLoader$LazyIterator.hasNext(ServiceLoader.java:393)
at java.util.ServiceLoader$1.hasNext(ServiceLoader.java:474)
at org.apache.commons.dbutils.BeanProcessor.callSetter(BeanProcessor.java:300)
at org.apache.commons.dbutils.BeanProcessor.populateBean(BeanProcessor.java:275)
at org.apache.commons.dbutils.BeanProcessor.populateBean(BeanProcessor.java:239)
at org.apache.commons.dbutils.BeanProcessor.toBean(BeanProcessor.java:154)
at
org.apache.commons.dbutils.BasicRowProcessor.toBean(BasicRowProcessor.java:123)
at org.apache.commons.dbutils.handlers.BeanHandler.handle(BeanHandler.java:80)
at org.apache.commons.dbutils.QueryRunner.query(QueryRunner.java:388)
at org.apache.commons.dbutils.QueryRunner.query(QueryRunner.java:347)
at EntryPoint$1.run(EntryPoint.java:26){code}
Seems like there is a race when propertyHandlers field in BeanProcessor is
accessing from multiple threads. Iterating ServiceLoader is not thread-safe.
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