In Spring framework we provide configuration data using which Spring container can instantiate beans and inject dependencies. Autowiring in Spring means Spring container can automatically resolve collaboration among beans (bean dependencies) by inspecting the contents of the ApplicationContext. Table of contents Spring Autowiring Modes Autowiring in Spring Enabling @Autowired annotation Using @Autowired annotation Using @Autowired annotation on setter Using @Autowired annotation on constructor Using @Autowired annotation on field Using @Autowired annotation on arbitrary methods required attr ..read more

In this post we’ll see what is circular dependency in Spring and how to resolve circular dependencies. Circular dependency in Spring If you mostly use constructor dependency injection, it is possible to create an unresolvable circular dependency scenario. For example; Class A requires an instance of class B through constructor injection, and class B requires an instance of class A through constructor injection. In such configuration where beans for classes A and B are to be injected into each other, the Spring IoC container can’t decide which bean should be created first and throws BeanCurrent ..read more

In Spring framework it is the Spring container that is responsible for instantiating beans, setting bean properties, wiring dependencies and managing the complete bean lifecycle from its instantiation to the time bean is destroyed. Table of contents Spring bean lifecycle callbacks Spring bean lifecycle callback methods Spring bean lifecycle callback methods execution order InitializingBean and DisposableBean callback interfaces InitializingBean and DisposableBean interfaces example Custom init and destroy methods in Spring bean lifecycle @PostConstruct and @PreDestroy annotations in Spring b ..read more

When you inject dependencies in Spring using value or ref attribute you can set a single primitive value or a single referenced bean. What if you want to inject a collection of values as a bean dependency in Spring, for that Spring framework provides an option to inject collections like List, Set, Map. Table of contents Injecting collection in Spring Injecting List and Set in Spring example Injecting Map and Props in Spring example Injecting bean reference in List, Set, Map Injecting collection in Spring In Spring framework the <list/>, <set/>, <map/>, and <props/> ..read more

In this post we’ll see how to inject null and empty string values into constructor argument or property in Spring. Injecting empty string in Spring In Spring if you have to set any property to the empty String value then pass (“”) as a value for that property. For example if you have an Employee bean and you want to set its email property to the empty String value (“”). <bean id="employeeBean" > <property name="email" value="" /> </bean> If injected as a constructor argument- <bean id="employeeBean" > <constructor-arg name="email" value="" /> </b ..read more

Autowiring in Spring makes life easy for the developer as the Spring container takes up the responsibility of autowiring relationships between collaborating beans by referring the contents of the ApplicationContext. Spring autowiring brings certain advantages at the same time autowiring has certain limitations and disadvantages. In this post we’ll have a look at both. Advantages of autowiring in Spring By using Autowiring there is a significant reduction in the explicit configuration needed to specify properties or constructor arguments. By using autowiring maintaining code and evolution of c ..read more