Top libraries every Java developer should know

There are some quite interesting java libraries out there that can help you write clean and efficient code and also improve your productivity. Here are some of the best java libraries that you should know.
Lombok
Are you still writing constructor, getter, and setter when creating a POJO class? Lombok is probably the best library to scaffold the repeating code in POJO classes. with the use of simple annotations in your POJO class Lombok will generate all the necessary methods based on the annotations used so you don’t have to write the same code again and again.
Hibernate
Hibernate lets you access and modify the data in DB without writing any queries. with the simple use of methods (in your repository classes) you can do most of the things that are required in most of the CRUD-based applications out there. it also lets you create your database tables from your POJO classes so you don't need to worry about creating tables or modifying them.
Google Guava
Google Guava is an open-source containing core Java libraries. Guava offers additional advanced features and functions to Java, some of these include new generic classes like multiset and bitmaps, strings, I/O, caches, graph libraries, etc. Guava has consistently been one of the most popular Java libraries.
Java Standard Libraries
Java standard libraries provided have some of the most robust and functional libraries. Java Standard libraries are often overlooked but they are quite handy if you know about them. Following are a few
- Java.util
- Java.lang
- Java.math
- Java.net
- Java.io /Java.nio
Mockito
Mockito is an open-source library for writing unit tests. Mockito helps in writing tests with clean and simple API. It enables developers to test double objects or dummy objects for behavior-driven and test-driven behavior. According to StackOverflow, Mockito was voted as the best mocking framework for Java.
Jackson
Jackson is known for its popularity and its high performance when it comes to JSON. it is used for serializing and deserializing Java object to JSON and vice versa. it also provides annotations binding on the POJO classes and it's very easy to use.
HttpClient
HttpClient is a network library that is used to request and retrieve HTTP resources over the network. It supports both synchronous and asynchronous programming models. HttpClient uses a builder pattern and the developer can use the created client to make multiple APIs calls with different configurations.
Log4j
Log4j is probably the most famous logging java library.
Logging events are imperative and logging libraries help developers to manage these log events. Log4j 2 has more advanced features than Log4j, some of which are:
- Improved filters and speed
- Extensibility and reliability
- Custom log levels
- Supports JSON, XML, and YAML
- Support for multiple APIs
- Performance of asynchronous loggers
- Clean configuration syntax