Java StringWriter

StringWriter is similar to StringBuffer, which can collect a host of string values and work with the data. We will explore writing a porting of a given string. Code sample:

Async Query Results

Repository queries can be executed asynchronously using @Async annotation. The result can be a Future, CompletableFuture and ListenableFuture. The method will return immediately upon invocation: @asyncFuture findByName(String name);@asyncCompletableFuture findByName(String name);@asyncListenableFuture

Return a MappingJacksonValue from a REST Controller

A proof of concept can be seen below: @GetMapping(“…”)public MappingJacksonValue fooMethod(…) throws JsonProcessingException { List foos = …; MappingJacksonValue wrapper = new MappingJacksonValue(fooa); … return wrapper;}

Unwrapping a Session from EntityManager

When we need access to a Hibernate Session, we have to unwrap it from the current EntityManager via the unwrap() method as follows: // Spring and Java EE EntityManager em

Selectively Expose CRUD Methods

When a repository interface should not be instantiated at runtime, it should be marked with @NoRepositoryBean annotation as follows: @NoRepositoryBeaninterface BaseRepository extends Repository { // CRUD methods that will not

Avoid Jackson Lazy Init Exceptions

First, add the following dependency to your project (Maven): com.fasterxml.jackson.datatype jackson-datatype-hibernate5 ${jackson.version} Further, add the following bean: @Beanpublic Module datatypeHibernateModule() { return new Hibernate5Module();}

Finding the Mime Type of a File

Finding the MIME type of a file is useful when you want to perform certain actions. PS: I have placed a file named nature.jpg in the folder /home/sridhar before executing