Skip to main content

Spring boot application events

Spring boot provides an easy and quick way to implement the event listeners. Spring boot generates multiple events during it's application lifecycle. We will see the below events which are provided by spring application under "org.springframework.boot.context.event" Java package. Thanks to spring that we don't need to focus on writing the listeners but the business logics which we want to execute during a specific event and to do that we just need to annotate our business method with @EventListener.

  • ApplicationContextInitializedEvent

Event published when a SpringApplication is starting up and the ApplicationContext is prepared and ApplicationContextInitializers have been called but before any bean definitions are loaded.

Implementation and code example

  • ApplicationEnvironmentPreparedEvent

Event published when a SpringApplication is starting up and the Environment is first available for inspection and modification.

Implementation and code example

  • ApplicationFailedEvent

Event published by a SpringApplication when it fails to start.

Implementation and code example

  • ApplicationPreparedEvent

Event published as when a SpringApplication is starting up and the ApplicationContext is fully prepared but not refreshed. The bean definitions will be loaded and the Environment is ready for use at this stage.
For implementation you can refer any of the other events defined here, for example:- ApplicationReadyEvent or ApplicationStartedEvent in below sections.

  • ApplicationReadyEvent

Event published as late as conceivably possible to indicate that the application is ready to service requests. The source of the event is the SpringApplication itself, but beware of modifying its internal state since all initialization steps will have been completed by then.

Implementation and code example

  • ApplicationStartedEvent

Event published once the application context has been refreshed but before any application and command line runners have been called.

Implementation and code example

  • ApplicationStartingEvent

Event published as early as conceivably possible as soon as a SpringApplication has been started - before the Environment or ApplicationContext is available, but after the ApplicationListeners have been registered. The source of the event is the SpringApplication itself, but beware of using its internal state too much at this early stage since it might be modified later in the lifecycle.

Implementation and code example


Popular Posts

Setting up kerberos in Mac OS X

Kerberos in MAC OS X Kerberos authentication allows the computers in same domain network to authenticate certain services with prompting the user for credentials. MAC OS X comes with Heimdal Kerberos which is an alternate implementation of the kerberos and uses LDAP as identity management database. Here we are going to learn how to setup a kerberos on MAC OS X which we will configure latter in our application. Installing Kerberos In MAC we can use Homebrew for installing any software package. Homebrew makes it very easy to install the kerberos by just executing a simple command as given below. brew install krb5 Once installation is complete, we need to set the below export commands in user's profile which will make the kerberos utility commands and compiler available to execute from anywhere. Open user's bash profile: vi ~/.bash_profile Add below lines: export PATH=/usr/local/opt/krb5/bin:$PATH export PATH=/usr/local/opt/krb5/sbin:$PATH export LDFLAGS=&

jaxb2-maven-plugin to generate java code from XSD schema

In this tutorial I will show how to generate the Java source code from XSD schema. I will use jaxb2-maven-plugin to generate the code using XSD file which will be declared in pom.xml to make it part of build, so when maven build is executed it will generate the java code using XSD. Class generation can be controlled in plugin configuration. Maven changes (pom.xml) Include below plugin in your pom.xml. Here we have done some configuration under configuration section as given below. schemaDirectory : This is the directory where I keep my schema (XSD file). outputDirectory : This is the java source location where I want to generate the Java files. If it is not given then by default it will be generate inside target folder. clearOutputDir : If this property is true then it will generate the classes on each build otherwise it will generate only if output directory is empty. <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>jaxb2-maven-plugin</art

SpringBoot - @ConditionalOnProperty example for conditional bean initialization

@ConditionalOnProperty annotation is used to check if specified property available in the environment or it matches some specific value so it can control the execution of some part of code like bean creation. It may be useful in many cases for example enable/disable service if specific property is available. Below are the attributes which can be used for property check. havingValue - Provide the value which need to check against specified property otherwise it will check that value should not be false. matchIfMissing - If true it will match the condition and execute the annotated code when property itself is not available in environment. name - Name of the property to be tested. If you want to test single property then you can directly put the property name as string like "" and if you have multiple properties to test then you can put the names like {"prop.name1","prop.name2"} prefix - It can be use when you want to apply some prefix to

Asynchronous REST service implementation in Spring boot

In this tutorial we will see how to create an asynchronous REST service endpoint using Spring boot application. Asynchronous service works in a way that it will not block the client request and do the processing in separate thread. When work is complete the response returned to the client so our service will be able to handle more client requests at the same time, compare to synchronous processing model. Let's understand how it is working in synchronous mode. In such server/client application at server side it has a pool of threads which are serving the request. If a request received by a thread then it will be blocked until it send the response back to client. In this case if processing doesn't take much time it will be able to process it quickly and accept other client requests but there could be one situation when all threads are busy and not able to accept the new client requests. To overcome of such problems, asynchronous processing model introduced for REST service