Top 9 Java Libraries Will Save Your More Time (Part 2)

In Java, we have tons of libraries are available and which can reduce your configuration efforts and also can save somewhat time to manage file structure for you; but here I created a listicle of the Top 9 Best Java libraries which I already used for our industrial and freelance projects in my career. I know the struggle is real.

I really support Open Source libraries/ecosystems and if they have better documentation, it will work definitely fine for you.

Here is the listicle for the best libraries to use in Java:

1. jHipster
2. Maven
3. Apache Commons
4. Google Gson
5. Hibernate-ORM
6. Junit
7. Mockito
8. Log4j and Slf4j
9. Java standard libraries

Note that, above 1-3 libraries were covered up in first part.

We are covering up bolded one in this article, please see another part for remaining details for amazing libraries to use in java.

4) Google Gson

Google-Gson helps convert Java objects to JSON and vice versa.

You don’t need to take care of serialization/deserialization while converting Java Objects into JSON and back. It will automatically handle everything.

This library is especially helpful when developing mobile applications and creating/using REST APIs as well as in any case you would need to convert a Java Object to its JSON representation and vice versa.

Here are some shortlisted goals:

Extensive support of Java Generics (I know, you hate generics!)

Allow custom representations for objects

Provide simple toJson() and fromJson() methods to convert Java objects to JSON and vice-versa

Allow pre-existing unmodifiable objects to be converted to and from JSON

Support arbitrarily complex objects (with deep inheritance hierarchies and extensive use of generic types)

You can find more about google-gson here.

5) Hibernate-ORM

Hibernate-ORM is an object-relational mapper. It’s used for persisting data in relational databases. It provides an easier and more abstract way of doing that for the developers. It uses JDBC in its implementation. Hibernate is also an implementation of the JPA (Java Persistence API) specification.

Hibernate supports lazy initialization, numerous fetching strategies, and optimistic locking with automatic versioning and time stamping. Hibernate requires no special database tables or fields and generates much of the SQL at system initialization time instead of at runtime.

Hibernate consistently offers superior performance over straight JDBC code, both in terms of developer productivity and runtime performance.

Do you think that JPA can replace the original Hibernate? — comment your thoughts below in the comments/response section.

You can find more about Hibernate ORM here.

6) Junit

It’s the next generation of JUnit. This includes focusing on Java 8 and above, as well as enabling many different styles of testing.

JUnit is a free Java framework for writing unit tests. It provides functionality for conducting repeatable tests on your code. You just need to be careful not to get obsessed with the numbers (% code coverage). Bigger code coverage does not always mean better and bug-less code.

You can use sonarqube to measure estimated code coverage by writing the test cases using JUnit. (This article contains how to set up sonarqube for your angular and java projects.)

You can find more about JUnit here.

7) Mockito

Despite the name, Mockito is not an alcohol-free mixed drink but instead a mocking framework. Hope some pickup lines may put more interest while reading the articles.

However, Mockito enables you to create mocks and write tests easier with simpler and cleaner code. What I felt while exploring JUnit is that “Writing great tests has never been easier! But using Mockito — it made my life tasty!”

It will also provide you better readability while writing test cases and also produces clean verification errors, so you never lose track while finding any anonymous errors.

You can find more about Mockito here.

8) Log4j and Slf4j

The two of these are both logging frameworks. Slf4j represents an abstraction for other logging frameworks (such as Log4j ). On the other hand, Log4j is just a simple logging framework. The latest version of Log4j is Log4j2, and it has awesome features to reduce your code load.

Do you know what you can do with these two library frameworks?

1. You can log your methods executions in external files, It will help you with reviewing/debugging the errors — Real-time Productions logs are much important to track issues.
2. You can send email notifications through the log4j2.xml file itself.
3. You can format your logs, error, info, warning, debug, etc. log levels.

You can find more about Log4j here and Slf4j here.

9) Java standard libraries

How can we forget the base of java, the standard libraries? They are also used by millions of developers worldwide. Lots of people underestimate the core libraries or maybe because of lacking knowledge with such libraries they never use it!

Let me put some light on major libraries:

• Use java.util, you can find all the collections and data structures available in Java
• Use java.math provides functionality for working with arbitrary-precision decimal (BigDecimal) and integer (BigInteger) values
• Use java.lang, it is always implicitly being imported as it contains everything you basically cannot program without String, Double, Enum, Math, etc.
• Use java.net, it is being used for working with sockets, creating connections, or in short — creating networking applications
• In Java we also have libraries for working with GUI : javax.swing (extension of the older java.awt)
• We even can play music and create MIDI (Musical Instrument Digital Interface) files with java.sound
• Use java.io, for reading files, working with pipes, Internal Memory Buffer Access, Inter-Thread Communication (Pipes), Buffering, Filtering, streams, and Network access.
• Use java.nio, which actually is the alternative to java.io and stands for non-blocking I/O. It allows intensive use of the input/output operations as you might guess.

You can find more about the Java Standard library here.

If you have any awesome library in your mind, feel free to add it in the comment/response section. I would like to explore new things deeply for sure.

References: Research and R&D from below documents/ communities/ websites.

Apache commons, Apache logging, Angular io official documents, Jhipster official website, Google Gson, Apache maven, oracle official documents, Junit Mockito official community, and spring io documents.

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© Originally Posted on 9Mood, also republished on Medium by Author Rakshit Shah (me).