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How-to articles, tricks, and solutions about SPRING

Spring Boot and multiple external configuration files

To use multiple external configuration files with Spring Boot, you can use the spring.config.name property to specify the names of the configuration files.

java spring spring-boot config

Spring cron expression for every day 1:01:am

To create a cron expression that triggers an event every day at 1:01 AM, you can use the following cron expression:

java spring cron cronexpression spring-scheduled

Spring MVC - How to return simple String as JSON in Rest Controller

To return a simple string as JSON in a Spring MVC Rest Controller, you can use the @ResponseBody annotation and return the string directly.

json java spring spring-mvc rest

Spring RestTemplate GET with parameters

To perform a GET request with parameters using the RestTemplate in Spring, you can use the getForObject() method and pass it a URL with placeholders for the parameters, as well as a map of the parameter values.

java spring rest

Understanding Spring @Autowired usage

The @Autowired annotation in Spring is used to inject dependencies into a Java object.

java spring autowired spring-3

UnsatisfiedDependencyException: Error creating bean with name

UnsatisfiedDependencyException is a runtime exception that is thrown when the Spring framework is unable to resolve a dependency for a bean.

java spring spring-mvc

Using env variable in Spring Boot's application.properties

You can use environment variables in your application.properties file by using the spring.profiles.active property.

java MySQL spring spring-mvc openshift

What's the difference between @Component, @Repository & @Service annotations in Spring?

In Spring, the @Component annotation is used to mark a Java class as a candidate for component scanning. The @Repository annotation is a specialization of @Component for use in the persistence layer.

java spring spring-mvc annotations

Why is my Spring @Autowired field null?

There are several reasons why an @Autowired field in a Spring bean might be null:

java null nullpointerexception spring autowired