QueryDB

  Suppose, I have a model like below -  public class A{ public List<String> phoneNumbers; } I want to apply @Max validation, so as to not allow phoneNumbers more then a certain limit. And, it is required to have this limit configurable in properties file.  By Default, @Max takes static values. We can not pass value read from application.properties to this annotation. So, we can write custom annotation like below -  import java.lang.annotation.Documented; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; import javax.validation.Constraint; import javax.validation.Payload; @Target({ ElementType.FIELD }) @Retention(RetentionPolicy.RUNTIME) @Documented @Constraint(validatedBy = FieldValidator.class) public @interface MaxAllowedSize { String message() default "size of list must be less than or equal to %s"; Class<?>[] groups() default {}; Class<? exte

  Spring JMS ActiveMQ - Listener Consumers getting hung or stuck after sometime i.e. the instances stop's consuming messages from AMQ after running for a while... On analyzing Thread Dump, we found following listener thread in parked status -  "Listener-1" #51 prio=5 os_prio=0 tid=0x00007fbc85599800 nid=0x2d016 waiting on condition [0x00007fbb3cc89000]    java.lang.Thread.State: WAITING (parking)        at sun.misc.Unsafe.park(Native Method)        - parking to wait for  <0x00000000b1da9348> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)        at java.util.concurrent.ArrayBlockingQueue.take(ArrayBlockingQueue.java:403)        at org.apache.activemq.transport.FutureResponse.getResult(FutureResponse.java:48) Thus, messages were no

 

 

  To compile code with mixed Java & Scala classes, add following to pom.xml  <build> <pluginManagement> <plugins> <plugin> <groupId>net.alchim31.maven</groupId> <artifactId>scala-maven-plugin</artifactId> <version>4.8.1</version> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.1</version> <configuration> <source>1.8</source> <target>1.8</target> </configuration> </plugin> </plugins> </pluginManagement> <plugins> <plugin> <groupId>net.alchim31.maven</groupId> <artifactId>scala-maven-plugin</artifactId> <executions> <execution> <id>scala-compile-fi