This is the first post from a series I plan to write; this series of posts will be about design patterns - those described by GoF (Gang of Four).
Design patterns described by GoF in their book (https://en.wikipedia.org/wiki/Design_Patterns) are divided into 3 types:
Creational (create objects for...
https://speakerdeck.com/vitalieb/efficient-logs-with-elastic-stack
Demo code available at https://github.com/vitalieb/ElasticStackPresentation
Introduction
Channels are used for routing messages to endpoints.
Channels do the routing and endpoints perform the operations.
Spring Integration (SI) provides numerous adapters for communication between different systems.
SI uses 3 types of components to construct its messaging architecture:
Advanced class design:
Anonymous classes are implicitly final and it can never be static.
static method > default method
default method > abstract method
default method > default method (re-declared with different implementation)
default method > static method
static method > non-static method
non-static method > static method
Static methods can never be abstract.
Static interface methods must be invoked using the interface name instead of reference variable - otherwise...
What is Spring Boot?
Spring Boot is a set of preconfigured framework that works on top of Spring Framework and simplifies configuring a Spring application.
What are the advantages of using Spring Boot?
Most important advantage is easy configuration of Spring application.
Additional to this it provides something more:
Integrated web containers that allow for easy testing
Starters - sets of dependencies that help...
What does REST stand for?
REST stands for REpresentational State Transfer.
What is a resource?
Anything that can be named is a resource. Usually that nouns that define our model.
What are safe REST operations?
Safe operations are operations that don't change things. These are:
GET
HEAD
OPTIONS
What are idempotent operations? Why is idempotency important?
Idempotent operations are operations that always return the same result....
What is the delegating filter proxy?
Delegating filter proxy is a servlet filter registered with the web container that delegates the requests to a Filter implementation on the Spring context side. That is there a 2 places servlet filters are attached to:
Web container
Spring context
As of Spring Security all requests pass through delegating filter proxy that is registered with the container...
Hibernate is an ORM framework that implements Java Persistence API (JPA).
For Hibernate to work we need 3 things:
Hibernate configuration (hibernate.properties or hibernate.cfg.xml)
Mapping metadata (XML or annotation-based) - info for instructing Hibernate on how the entities have to be mapped to DB tables. Mapping metadata contains persistence unit info. Persistence unit - per database mapping configuration + some other...
What is the difference between checked and unchecked exceptions?
Checked exceptions are exceptions that are checked at compile time - that fact enforces the developer to either catch it and handle or declare as being thrown and it will be propagated in call stack. Unchecked exceptions are not checked at compile time.
Why do we (in Spring) prefer unchecked exceptions?
Spring prefers...