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ORA-12518, TNS:listener could not hand off client connection comes from a loop with heavy memory access

I have a loop with heavy memory access from oracle.
int firstResult = 0;
int maxResult = 500;
int targetTotal = 8000; // more or less
int phase = 1;
for (int i = 0; i<= targetTotal; i += maxResult) {
try {
Session session = .... init hibernate session ...
// Start Transaction
List<Accounts> importableInvAcList = ...getting list using session and firstResult-maxResult...
List<ContractData> dataList = new ArrayList<>();
List<ErrorData> errorDataList = new ArrayList<>();
for (Accounts account : importableInvAcList) {
... Converting 500 Accounts object to ContractData object ...
... along with 5 more database call using existing session ...
.. On converting The object we generate thousands of ErrorData...
dataList.add(.. converted account to Contract data ..);
errorDataList.add(.. generated error data ..);
}
dataList.stream().forEach(session::save); // 500 data
errorDataList.stream().forEach(session::save); // 10,000-5,000 data
... Commit Transaction ...
phase++;
} catch (Exception e) {
return;
}
}
On the second phase (2nd loop) the Exception comes out. Sometimes Exception is coming out in 3rd or fifth phase.
I also checked the Runtime Memory.
Runtime runtime = Runtime.getRuntime();
long total = runtime.totalMemory();
long free = runtime.freeMemory();
long used = total - free;
long max = runtime.maxMemory();
And in the second phase the status was below for sample...
Used: 1022 MB, Free: 313 MB, Total Allocated: 1335 MB
Stack Trace is here...
org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:140)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:128)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:142)
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:85)
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1463)
at ibbl.remote.tx.TxSessionImpl.beginTx(TxSessionImpl.java:41)
at ibbl.remote.tx.TxController.initPersistence(TxController.java:70)
at com.ibbl.data.util.CDExporter2.run(CDExporter2.java:130)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.sql.SQLException: Listener refused the connection with the following error:
ORA-12518, TNS:listener could not hand off client connection
Noted that, this process running in a Thread, and there are 3 similar Thread running at a time.
Why this Exception hangs out after the loop running a while ?

there are 3 similar Thread running at a time.
If your code creates a total of 3 Threads, then, optimally, you need only 3 Oracle Connections. Create all of them before any Thread is created. Create the Threads, assign each Thread a Connection, then start the Threads.
Chances are good, though, that your code might be way too aggressively consuming resources on whatever machine is hosting it. Even if you eliminate the ORA-12518, the RDBMS server may "go south". By "go south", I mean if your application is consuming too many resources the machine hosting it or the machine hosting the RDBMS server may "panic" or something equally dreadful.

Gets an error error in Kafka producer when creating topic but the topic is created on the Kafka server

I'm using Kafka producer 10.2.1 to create a topic and to write to topic, when I create the topic I get the following error, but the topic is created:
java.util.concurrent.ExecutionException: org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 60000 ms.
at org.apache.kafka.clients.producer.KafkaProducer$FutureFailure.<init>(KafkaProducer.java:774)
at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:494)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:440)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:360)
at kafka.AvroProducer.produce(AvroProducer.java:47)
at samples.TestMqttSource.messageReceived(TestMqttSource.java:89)
at mqtt.JsonConsumer.messageArrived(JsonConsumer.java:132)
at org.eclipse.paho.client.mqttv3.internal.CommsCallback.deliverMessage(CommsCallback.java:477)
at org.eclipse.paho.client.mqttv3.internal.CommsCallback.handleMessage(CommsCallback.java:380)
at org.eclipse.paho.client.mqttv3.internal.CommsCallback.run(CommsCallback.java:184)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 60000 ms.
msg org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 60000 ms.
loc org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 60000 ms.
cause org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 60000 ms.
excep java.util.concurrent.ExecutionException: org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 60000 ms.
All suggestions is highly appreciated.

You can't use KafkaProducer to create a topic (So I'm not quite sure how you managed to create the topic, unless you did it previously via a different method such as the kafka admin shell scripts). Instead you use the AdminUtils supplied by Kafka library.
I recently achieved both of the requirements you are after, and you'd be surprised how easy it is to achieve. Below is a simple code example showing you how to create a topic via AdminUtils, and how to then write to it.
class Foo {
private String TOPIC = "testingTopic";
private int NUM_OF_PARTITIONS = 10;
private int REPLICATION_FACTOR = 1;
public Foo() {
ZkClient zkClient = new ZkClient( "localhost:2181", 15000, 10000, ZKStringSerializer$.MODULE$ );
ZkUtils zkUtils = new ZkUtils( zkClient, new ZkConnection( "localhost:2181" ), false);
if ( !AdminUtils.topicExists(zkUtils, TOPIC) ) {
try {
AdminUtils.createTopic(zkUtils, TOPIC, NUM_OF_PARTITIONS, REPLICATION_FACTOR, new Properties(), Enforced$.MODULE$);
Properties producerConfig = new Properties();
producerConfig.put(ProducerConfig.BOOTSTRAP_SERVER_CONFIG, "localhost:9092");
producerConfig.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.ByteArraySerializer");
producerConfig.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
KafkaProducer<String, String> producer = new KafkaProducer<>(producerConfig);
// This is just to show you how to write but you could be more elaborate
int i = 0;
while ( i < 11 ) {
ProducerRecord<String, String> rec = new ProducerRecord<>(TOPIC, ("This is line number " + i));
producer.send(rec);
i++;
}
producer.closer();
} catch ( AdminOperationException aoe ) {
aoe.printStackTrace();
}
}
}
}
Remember that if you want to delete topics, by default in the settings this is disabled. The config file you use when starting Kafka (by default it is ${kafka_home}/config/server.properties), add the following line if it doesn't already exist and is set to false or commented out:
delete.topic.enabled=true
You'll then have to restart the server and can delete topics either via Java or the command line tools supplied.
NB
It's always a good idea to close producers / consumers when you are finished with them, as shown in the code example.

Why this exception is getting occurred while running the java code with Spark and Stanford NLP?

Here is my code:
try
{
Dataset<Row> df = spark.sql("select answer from health where limit 1");
nameAndCity = df.toJavaRDD().map(new Function<Row, String>() {
// #Override
public String call(Row row) {
return row.getString(0);
}
}).collect();
}
catch (Exception AnalysisException)
{
System.out.print("\nTable is not found\n");
}
spark.close();
System.out.println("Spark Done....!");
for (String name : nameAndCity)
{
Annotation document = new Annotation(name);
Properties props = new Properties();
props.setProperty("annotators", "tokenize,ssplit,pos,lemma,ner,parse,sentiment");
//props.setProperty("parse.binaryTrees","true");
StanfordCoreNLP pipeline = new StanfordCoreNLP(props);
pipeline.annotate(document);
for (CoreMap sentence : document.get(CoreAnnotations.SentencesAnnotation.class)) {
System.out.println("---");
System.out.println("Sentence Analyzed: " + " " + sentence.get(CoreAnnotations.TextAnnotation.class));
System.out.println("Reflected sentiment: " + " " + sentence.get(SentimentCoreAnnotations.SentimentClass.class));
}
}
After running this code, I get the following exception:
Exception in thread "main" edu.stanford.nlp.util.ReflectionLoading$ReflectionLoadingException: Error creating edu.stanford.nlp.time.TimeExpressionExtractorImpl
at edu.stanford.nlp.util.ReflectionLoading.loadByReflection(ReflectionLoading.java:40)
at edu.stanford.nlp.time.TimeExpressionExtractorFactory.create(TimeExpressionExtractorFactory.java:57)
at edu.stanford.nlp.time.TimeExpressionExtractorFactory.createExtractor(TimeExpressionExtractorFactory.java:38)
at edu.stanford.nlp.ie.regexp.NumberSequenceClassifier.<init>(NumberSequenceClassifier.java:86)
at edu.stanford.nlp.ie.NERClassifierCombiner.<init>(NERClassifierCombiner.java:136)
at edu.stanford.nlp.pipeline.AnnotatorImplementations.ner(AnnotatorImplementations.java:121)
at edu.stanford.nlp.pipeline.AnnotatorFactories$6.create(AnnotatorFactories.java:273)
at edu.stanford.nlp.pipeline.AnnotatorPool.get(AnnotatorPool.java:152)
at edu.stanford.nlp.pipeline.StanfordCoreNLP.construct(StanfordCoreNLP.java:451)
at edu.stanford.nlp.pipeline.StanfordCoreNLP.<init>(StanfordCoreNLP.java:154)
at edu.stanford.nlp.pipeline.StanfordCoreNLP.<init>(StanfordCoreNLP.java:150)
at edu.stanford.nlp.pipeline.StanfordCoreNLP.<init>(StanfordCoreNLP.java:137)
at spark.sparkhive.queryhive.main(queryhive.java:64)
Caused by: edu.stanford.nlp.util.MetaClass$ClassCreationException: MetaClass couldn't create public edu.stanford.nlp.time.TimeExpressionExtractorImpl(java.lang.String,java.util.Properties) with args [sutime, {}]
at edu.stanford.nlp.util.MetaClass$ClassFactory.createInstance(MetaClass.java:237)
at edu.stanford.nlp.util.MetaClass.createInstance(MetaClass.java:382)
at edu.stanford.nlp.util.ReflectionLoading.loadByReflection(ReflectionLoading.java:38)
... 12 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at edu.stanford.nlp.util.MetaClass$ClassFactory.createInstance(MetaClass.java:233)
... 14 more
Caused by: java.lang.NoClassDefFoundError: de/jollyday/ManagerParameter
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at edu.stanford.nlp.time.Options.<init>(Options.java:87)
at edu.stanford.nlp.time.TimeExpressionExtractorImpl.init(TimeExpressionExtractorImpl.java:44)
at edu.stanford.nlp.time.TimeExpressionExtractorImpl.<init>(TimeExpressionExtractorImpl.java:39)
... 19 more
Caused by: java.lang.ClassNotFoundException: de.jollyday.ManagerParameter
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 24 more
17/02/22 18:26:39 INFO ShutdownHookManager: Shutdown hook called
17/02/22 18:26:39 INFO ShutdownHookManager: Deleting directory /tmp/spark-23b5fac2-27ec-44a6-9ff7-cb2b8bfd8753
Why I am getting this exception and what I should do to resolve it?

This one is the source of your trouble:
java.lang.NoClassDefFoundError: de/jollyday/ManagerParameter
Your program is looking for this class but can't find it. Check your classpath.
You can ignore the preceding exceptions in the output because they're just reactions to the original exception.
ReflectionLoadingException is thrown by a method called loadByReflection, so it seems to be a wrapper exception of some kind and unlikely to tell you much.
Then we have ClassCreationException thrown by createInstance, kind of the same situation. In general if you have a method called doSomething that throws DoSomethingException, the exception is either going to tell you exactly what the problem is ("x must be >= 100") or wrap the actual exception.
InvocationTargetException is just the exception that the JVM throws when you try to invoke a method using reflection and that method throws an exception. Again it's just a wrapper for the actual exception.
Finally we get to the actual exception, NoClassDefFoundError.

Alternatives to sleep when checking if Netty server is up?

I am starting Netty with a rest interface. I get this exception:
javax.ws.rs.ProcessingException: RESTEASY004655: Unable to invoke request
at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:287)
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.invoke(ClientInvocation.java:436)
at org.jboss.resteasy.client.jaxrs.internal.proxy.ClientInvoker.invoke(ClientInvoker.java:102)
at org.jboss.resteasy.client.jaxrs.internal.proxy.ClientProxy.invoke(ClientProxy.java:64)
at com.sun.proxy.$Proxy20.ping(Unknown Source)
at com.openet.atf.agent.proxy.SlaveRemoteProxy.ping(SlaveRemoteProxy.java:41)
at com.openet.atf.agent.manage.Master.startSlaves(Master.java:86)
at com.openet.acceptance.runner.AcceptanceRunner.main(AcceptanceRunner.java:195)
Caused by: org.apache.http.conn.HttpHostConnectException: Connection to http://ovm1:8889 refused
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:190)
at org.apache.http.impl.conn.ManagedClientConnectionImpl.open(ManagedClientConnectionImpl.java:294)
at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:645)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:480)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:283)
... 7 more
Caused by: java.net.ConnectException: Connection refused
I prevented this from happening by doing a Thread.sleep(5000);. I am looking for a better alternative to sleep. Sleep always assumes that the length of time is 5 seconds.

A common approach used in situations where success could be any time in the future is the back off pattern, typically implemented by doubling the wait time every iteration.
Something like this:
long wait = 50; // ms
boolean connected;
while (!connected) {
Thread.sleep(wait);
connected = <code to check connection>
wait *= 2;
}

You can sleep until the connection is established.
boolean up = false;
while (!up) {
try {
// Try to connect
up = true;
} catch (Exception e) {
Thread.sleep(5000);
}
}

"ConnectionPoolTimeoutException" when iterating objects in S3

I've been working for some time with aws java API with not so many problems. Currently I'm using the library 1.5.2 version.
When I'm iterating the objects inside a folder with the following code:
AmazonS3 s3 = new AmazonS3Client(new PropertiesCredentials(MyClass.class.getResourceAsStream("AwsCredentials.properties")));
String s3Key = "folder1/folder2";
String bucketName = Constantes.S3_BUCKET;
String key = s3Key +"/input_chopped/";
ObjectListing current = s3.listObjects(new ListObjectsRequest()
.withBucketName(bucketName)
.withPrefix(key));
boolean siguiente = true;
while (siguiente) {
siguiente &= current.isTruncated();
contador += current.getObjectSummaries().size();
for (S3ObjectSummary objectSummary : current.getObjectSummaries()) {
S3Object object = s3.getObject(new GetObjectRequest(bucketName, objectSummary.getKey()));
System.out.println(object.getKey());
}
current=s3.listNextBatchOfObjects(current);
}
Gist: Link: https://gist.github.com/fgblanch/6038699
I'm getting the following exception:
INFO (AmazonHttpClient.java:358) - Unable to execute HTTP request: Timeout waiting for connection from pool
org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection from pool
at org.apache.http.impl.conn.PoolingClientConnectionManager.leaseConnection(PoolingClientConnectionManager.java:232)
at org.apache.http.impl.conn.PoolingClientConnectionManager$1.getConnection(PoolingClientConnectionManager.java:199)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:456)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:784)
at com.amazonaws.http.AmazonHttpClient.executeHelper(AmazonHttpClient.java:315)
at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:199)
at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:2994)
at com.amazonaws.services.s3.AmazonS3Client.getObject(AmazonS3Client.java:918)
at com.madiva.segmentacion.tests.ListaS3.main(ListaS3.java:177)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caught an AmazonClientException, which means the client encountered a serious internal problem while trying to communicate with S3, such as not being able to access the network.
Error Message: Unable to execute HTTP request: Timeout waiting for connection from pool
Any idea how to avoid this error. It only happens in folders with a number of object , in this case there were 463 files inside. Thanks

I've found that S3Object opens a connection for each object. That are not liberated even if the object is garbage collected so it is needed to execute object.close(), in order to liberate the connection to the pool.
So the corrected code would be:
for (S3ObjectSummary objectSummary : current.getObjectSummaries()) {
S3Object object = s3.getObject(new GetObjectRequest(bucketName, objectSummary.getKey()));
System.out.println(object.getKey());
object.close();
}

Check if HttpResponseHandler is closing connections from the pool.
AmazonHttpClient has the paramter 'leaveHttpConnectionOpen' which indicates that the connection should be closed or not.