Programming Articles - Page 1727 of 3366

Executor framework are designed using thread pool concept. Thread pool is the way to reuse the already created thread instead of creating a new thread every time to execute the current task.Executors class provides a factory method to create thread pools. The ThreadPoolExecutor class is the base implementation for the executors that are returned from many of the Executors  factory methods.Sr. No.KeyFixed Thread PoolCached Thread Pool1BasicAs per Java Doc −Creates a thread pool that reuses a fixed number of threads operating off a shared unbounded queue. At any point, at most nThreads threads will be active processing tasks. If additional ... Read More

Executor and ExecutorServices both interfaces are part of the Executor framework. It is released with Java 5. In java, thread creation is very expensive operation so we should  reuse the available thread instead of starting a new thread every time and we can achieve the same using Executor framework.Executor framework use the thread pool to execute the task parallel which helps to optimize response time and resource utilization. It provides four types of built in thread pools −Fixed Thread PoolCached Thread PoolScheduled Thread PoolSingle Thread ExecutorSr. No.KeyExecutorExecutorServices1BasicIt is a parent interfaceIt extends Executor Interface2MethodIt has execute() methodIt has submit() method3Return TypeIt ... Read More

Runnable and Callable both functional interface. Classes which are implementing these interfaces are designed to be executed by another thread.Thread can be started with Ruunable and they are two ways to start a new thread: one is by subclassing Thread class and another is implementing Runnable interface.Thread class does not have constructor for callable so we should use ExecutorService  class for executing thread.Sr. No.KeyRunnableCallable1PackageIt belongs to Java.langIt belongs to java.util.concurrent2Thread CreationWe can create thread by passing runnable as a parameter.We can’t create thread by passing callable as parameter  3Return TypeRuunable does not return anythingCallable can return results4.MethodIt has run() methodIt ... Read More

Java Collections framework is used for storing and manipulating group of data. It is an in-memory data structure and every element in the collection should be computed before it can be added in the collections.Stream API is only used for processing group of data. It does not modify the actual collection, they only provide the result as per the pipelined methods.Sr. No.KeyCollectionsStreams1BasicIt is used for storing and manipulating group of dataStream API is only used for processing group of data2PackageAll the classes and interfaces of this API is in the Java.util packageAll the classes and interfaces of this API is ... Read More

Spring AOP is proxy based. Spring used two types of proxy strategy one is JDK dynamic proxy and other one is CGLIB proxy.JDK dynamic proxy is available with the JDK. It can be only proxy by interface so target class needs to implement interface. In your is implementing one or more interface then spring will automatically use JDK dynamic proxies.On the other hand, CGLIB is a third party library which spring used for creating proxy. It can create proxy by subclassing. Spring uses CGLIB for proxy if class is not implementing interface.Sr. No.KeyJDK dynamic proxyCGLIB proxy1BasicIt can be only proxy ... Read More

Applicationcontext.xml - It is standard spring context file which contains all beans and the configuration  that are common among all the servlets. It is optional file in case of web app. Spring uses ContextLoaderListener to load this file in case of web application. Spring-servlet.xml- It is a single entry point for Spring. DispatcherServlet scan this file and starts to load its component. It defines the bean and configuration that are only related to that servlet.In Spring MVC application we chain them in below order −          web.xml --> dispatcher servlet --> application contextSr. No.KeyApplicationContext.xmlSpring-servlet.xml1BasicapplicationContext.xml  defines the beans that ... Read More

ContextLoaderListener creates a root web-application-context for the web-application and puts it in the ServletContext. This context can be used to load and unload the spring-managed beans ir-respective of what technology is being used in the controller layer(Struts or Spring MVC).DispatcherServlet creates its own WebApplicationContext and the handlers/controllers/view-resolvers are managed by this context.Sr. No.KeyDispatcherServletContextLoaderListener1BasicThe task of the DispatcherServlet  is to send request to the specific Spring MVC controller ContextLoaderListener  reads the Spring configuration file (with value given against contextConfigLocation in web.xml ), parses it and loads the singleton bean defined in that config file. So we initialize the web application with ContextLoaderListener ... Read More

@Inject and @Autowired both annotations are used for autowiring in your application.@Inject annotation is part of Java CDI which was introduced in Java 6, whereas @Autowire annotation is part of spring framework. Both annotations fulfill same purpose therefore, anything of these we can use in our application.Sr. No.Key@Inject@Autowired1BasicIt is part of Java CDIIt is part of Spring framework2RequiredIt has no required attributeIt has required attribute3Default ScopeDefault scope of the autowired beans is SingletonDefault scope of the inject beans is prototype4AmbiguityIn case of ambiguity in beans for injection then @Named qualifier should be added in your code.In case of ambiguity in ... Read More

Sr. No.KeySpring AOPAspectJ AOP1BasicIt is a simple implementation of AOP technology. It can be applied only the beans.It is a complete implementation of the AOP technology in Java. It can be applied in any java class.2Design Pattern  It uses the proxy pattern so aspects are applied on proxies objectIt doesn't use proxy pattern aspects are directly applied on the code.3PontCutsIt supports only method level points cutsNo Restriction4Weaving of AspectsThe weaving of Aspects will be performed by the container at container start-up Weaving of aspect can perform with a post compilation of your code through bytecode modification5Nested MethodAspects can’t be applied when ... Read More

Spring framework supports five types of bean scope −SingletonPrototypeRequestSessionGlobal SessionAs per the spring documentation −Singleton − It returns a single bean instance per Spring IoC container. This single instance is stored in a cache of such singleton beans, and all subsequent requests and references for that named bean return the cached object.Spring singleton is different than Java singleton. In java, one instance of the bean is created per JVM whereas in spring, one instance of the bean is created per application context.Proptype −As per the spring documentation −Spring does not manage the complete lifecycle of a prototype bean: the container ... Read More