NPE from SemaphoreConcurrentLinkedDequeManagedConnectionPool.returnForFrequencyCheck ------------------------------------------------------------------------------------ Key: JBJCA-1362 URL: https://issues.jboss.org/browse/JBJCA-1362 Project: IronJacamar Issue Type: Bug Components: Core Reporter: Osamu Nagano Priority: Major NPE happens in the ConnectionValidator thread, about once a week on EAP 7.0.7 (IronJacamar 1.3.7.Final-redhat-1). {code} 2017-11-23 14:02:49,527 WARN [org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator] (ConnectionValidator) IJ000602: ConnectionValidator ignored unexpected runtime exception: java.lang.NullPointerException at java.util.concurrent.ConcurrentLinkedDeque.checkNotNull(ConcurrentLinkedDeque.java:798) at java.util.concurrent.ConcurrentLinkedDeque.linkLast(ConcurrentLinkedDeque.java:386) at java.util.concurrent.ConcurrentLinkedDeque.addLast(ConcurrentLinkedDeque.java:903) at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.returnForFrequencyCheck(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:1597) at org.jboss.jca.core.connectionmanager.pool.mcp.SemaphoreConcurrentLinkedDequeManagedConnectionPool.validateConnections(SemaphoreConcurrentLinkedDequeManagedConnectionPool.java:1523) at org.jboss.jca.core.connectionmanager.pool.validator.ConnectionValidator$ConnectionValidatorRunner.run(ConnectionValidator.java:277) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745) {code} Configuration: {code} <datasource jndi-name="java:/DB1" pool-name="DB1" statistics-enabled="true"> <connection-url>jdbc:oracle:thin:@ServerA:1521:DB1</connection-url> <driver-class>oracle.jdbc.OracleDriver</driver-class> <connection-property name="v$session.program"> ServerA </connection-property> <driver>oracle</driver> <pool> <min-pool-size>490</min-pool-size> <initial-pool-size>490</initial-pool-size> <max-pool-size>490</max-pool-size> <prefill>true</prefill> <allow-multiple-users>false</allow-multiple-users> </pool> <security> <user-name>username</user-name> <password>password</password> </security> <validation> <check-valid-connection-sql>SELECT 1 FROM DUAL</check-valid-connection-sql> <validate-on-match>false</validate-on-match> <background-validation>true</background-validation> <background-validation-millis>120000</background-validation-millis> </validation> <timeout> <blocking-timeout-millis>3000</blocking-timeout-millis> <allocation-retry>10</allocation-retry> <allocation-retry-wait-millis>60000</allocation-retry-wait-millis> </timeout> <statement> <prepared-statement-cache-size>10</prepared-statement-cache-size> </statement> </datasource> {code}