Java Spring Multiple Choice Questions & Answers (MCQs) on “JMX MBeans”.
1. There are two main options for scheduling tasks on the Java platform:-
a) JDK Timer
b) Quartz Scheduler
c) All of the mentioned
d) None of the mentioned
Answer: c
Clarification: JDK Timer offers simple task scheduling features that you can use conveniently because the features are bundled with JDK. Compared with JDK Timer, Quartz offers more powerful job scheduling features.
2. Spring supports JMX by allowing you to export any beans in its IoC container as model MBeans.
a) True
b) False
Answer: a
Clarification: This can be done simply by declaring an MBeanExporter instance.
3. Connectors to expose your MBeans for remote access over a specific protocol by using a factory bean.
a) MBeanExporter
b) JSR-160
c) All of the mentioned
d) None of the mentioned
Answer: c
Clarification: In addition, Spring enables you to declare JSR-160 (Java Management Extensions Remote API) connectors to expose your MBeans for remote access over a specific protocol by using a factory bean. Spring provides factory beans for both servers and clients.
4. Spring can also detect and export your MBeans automatically from beans declared in the IoC container and annotated with JMX-specific annotations defined by Spring.
a) True
b) False
Answer: a
Clarification: The MBeanExporter class exports beans, delegating to an instance of MBeanInfoAssembler to do the heavy lifting.
5. Method, all files in the source directory will be replicated to the destination directory.
a) replicate
b) copy
c) rep
d) none of the mentioned
Answer: a
Clarification: Each time you call the replicate() method, all files in the source directory will be replicated to the destination directory. To avoid unexpected problems caused by concurrent replication, you declare this method as synchronized.
6. To register an MBean, you need an instance of the interface :-
import java.lang.management.ManagementFactory; import javax.management.Descriptor; import javax.management.JMException; import javax.management.MBeanServer; import javax.management.ObjectName; import javax.management.modelmbean.DescriptorSupport; import javax.management.modelmbean.InvalidTargetObjectTypeException; import javax.management.modelmbean.ModelMBeanAttributeInfo; import javax.management.modelmbean.ModelMBeanInfo; import javax.management.modelmbean.ModelMBeanInfoSupport; import javax.management.modelmbean.ModelMBeanOperationInfo; import javax.management.modelmbean.RequiredModelMBean; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main {<code>code> public static void main(String[] args) throws IOException { ApplicationContext context = new ClassPathXmlApplicationContext("beans-jmx.xml"); FileReplicator documentReplicator = (FileReplicator) context.getBean("documentReplicator"); try { MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer(); ObjectName objectName = new ObjectName("bean:name=documentReplicator"); RequiredModelMBean mbean = new RequiredModelMBean(); mbean.setManagedResource(documentReplicator, "objectReference"); Descriptor srcDirDescriptor = new DescriptorSupport(new String[] { "name=SrcDir", "descriptorType=attribute", "getMethod=getSrcDir", "setMethod=setSrcDir" }); ModelMBeanAttributeInfo srcDirInfo = new ModelMBeanAttributeInfo( "SrcDir", "java.lang.String", "Source directory", true, true, false, srcDirDescriptor); Descriptor destDirDescriptor = new DescriptorSupport(new String[] { "name=DestDir", "descriptorType=attribute", "getMethod=getDestDir", "setMethod=setDestDir" }); public static void main(String[] args) throws IOException { ApplicationContext context = new ClassPathXmlApplicationContext("beans-jmx.xml"); FileReplicator documentReplicator = (FileReplicator) context.getBean("documentReplicator"); ModelMBeanAttributeInfo destDirInfo = new ModelMBeanAttributeInfo( "DestDir", "java.lang.String", "Destination directory", true, true, false, destDirDescriptor); ModelMBeanOperationInfo getSrcDirInfo = new ModelMBeanOperationInfo( "Get source directory", FileReplicator.class.getMethod("getSrcDir")); ModelMBeanOperationInfo setSrcDirInfo = new ModelMBeanOperationInfo( "Set source directory", FileReplicator.class.getMethod("setSrcDir", String.class)); ModelMBeanOperationInfo getDestDirInfo = new ModelMBeanOperationInfo( "Get destination directory", FileReplicator.class.getMethod("getDestDir")); ModelMBeanOperationInfo setDestDirInfo = new ModelMBeanOperationInfo( "Set destination directory", FileReplicator.class.getMethod("setDestDir", String.class)); ModelMBeanOperationInfo replicateInfo = new ModelMBeanOperationInfo( "Replicate files", FileReplicator.class.getMethod("replicate")); ModelMBeanInfo mbeanInfo = new ModelMBeanInfoSupport( "FileReplicator", "File replicator", new ModelMBeanAttributeInfo[] { srcDirInfo, destDirInfo }, null, new ModelMBeanOperationInfo[] { getSrcDirInfo, setSrcDirInfo, getDestDirInfo, setDestDirInfo, replicateInfo }, null); mbean.setModelMBeanInfo(mbeanInfo); mbeanServer.registerMBean(mbean, objectName); } catch (JMException e) { ... } catch (InvalidTargetObjectTypeException e) { ... } catch (NoSuchMethodException e) { ... } System.in.read(); } }
a) javax.management.MBeanServer
b) javax.management
c) javax.management.MBean
d) none of the mentioned
Answer: a
Clarification: To register an MBean, you need an instance of the interface javax.management.MBeanServer.
7.The static method to locate a platform MBean server.
import java.lang.management.ManagementFactory; import javax.management.Descriptor; import javax.management.JMException; import javax.management.MBeanServer; import javax.management.ObjectName; import javax.management.modelmbean.DescriptorSupport; import javax.management.modelmbean.InvalidTargetObjectTypeException; import javax.management.modelmbean.ModelMBeanAttributeInfo; import javax.management.modelmbean.ModelMBeanInfo; import javax.management.modelmbean.ModelMBeanInfoSupport; import javax.management.modelmbean.ModelMBeanOperationInfo; import javax.management.modelmbean.RequiredModelMBean; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main { public static void main(String[] args) throws IOException { ApplicationContext context = new ClassPathXmlApplicationContext("beans-jmx.xml"); FileReplicator documentReplicator = (FileReplicator) context.getBean("documentReplicator"); try { MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer(); ObjectName objectName = new ObjectName("bean:name=documentReplicator"); RequiredModelMBean mbean = new RequiredModelMBean(); mbean.setManagedResource(documentReplicator, "objectReference"); Descriptor srcDirDescriptor = new DescriptorSupport(new String[] { "name=SrcDir", "descriptorType=attribute", "getMethod=getSrcDir", "setMethod=setSrcDir" }); ModelMBeanAttributeInfo srcDirInfo = new ModelMBeanAttributeInfo( "SrcDir", "java.lang.String", "Source directory", true, true, false, srcDirDescriptor); Descriptor destDirDescriptor = new DescriptorSupport(new String[] { "name=DestDir", "descriptorType=attribute", "getMethod=getDestDir", "setMethod=setDestDir" }); public static void main(String[] args) throws IOException { ApplicationContext context = new ClassPathXmlApplicationContext("beans-jmx.xml"); FileReplicator documentReplicator = (FileReplicator) context.getBean("documentReplicator"); ModelMBeanAttributeInfo destDirInfo = new ModelMBeanAttributeInfo( "DestDir", "java.lang.String", "Destination directory", true, true, false, destDirDescriptor); ModelMBeanOperationInfo getSrcDirInfo = new ModelMBeanOperationInfo( "Get source directory", FileReplicator.class.getMethod("getSrcDir")); ModelMBeanOperationInfo setSrcDirInfo = new ModelMBeanOperationInfo( "Set source directory", FileReplicator.class.getMethod("setSrcDir", String.class)); ModelMBeanOperationInfo getDestDirInfo = new ModelMBeanOperationInfo( "Get destination directory", FileReplicator.class.getMethod("getDestDir")); ModelMBeanOperationInfo setDestDirInfo = new ModelMBeanOperationInfo( "Set destination directory", FileReplicator.class.getMethod("setDestDir", String.class)); ModelMBeanOperationInfo replicateInfo = new ModelMBeanOperationInfo( "Replicate files", FileReplicator.class.getMethod("replicate")); ModelMBeanInfo mbeanInfo = new ModelMBeanInfoSupport( "FileReplicator", "File replicator", new ModelMBeanAttributeInfo[] { srcDirInfo, destDirInfo }, null, new ModelMBeanOperationInfo[] { getSrcDirInfo, setSrcDirInfo, getDestDirInfo, setDestDirInfo, replicateInfo }, null); mbean.setModelMBeanInfo(mbeanInfo); mbeanServer.registerMBean(mbean, objectName); } catch (JMException e) { ... } catch (InvalidTargetObjectTypeException e) { ... } catch (NoSuchMethodException e) { ... } System.in.read(); } }
a) ManagementFactory.getPlatform()
b) ManagementFactory.getPlatformMBeanServer()
c) ManagementFactory.getPlatformMBean()
d) All of the mentioned