Compare Web3j to these popular alternatives based on real-world usage and developer feedback.

The Guava project contains several of Google's core libraries that we rely on in our Java-based projects: collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and so forth.

A decentralized platform for applications that run exactly as programmed without any chance of fraud, censorship or third-party interference.

It is a revolutionary release of the world’s no 1 development platform. It includes a huge upgrade to the Java programming model and a coordinated evolution of the JVM, Java language, and libraries. Java 8 includes features for productivity, ease of use, improved polyglot programming, security and improved performance.

It is a "template engine"; a generic tool to generate text output (anything from HTML to auto generated source code) based on templates. It's a Java package, a class library for Java programmers.

A library for composing asynchronous and event-based programs by using observable sequences for the Java VM.
It is a suite of data-processing tools for Java (and the JVM platform), including the flagship streaming JSON parser / generator library, matching data-binding library (POJOs to and from JSON) and additional data format modules to process data encoded in Avro, BSON, CBOR, CSV, Smile, (Java) Properties, Protobuf, XML or YAML; and even the large set of data format modules to support data types of widely used data types such as Guava, Joda.

It tailors your application for GraalVM and HotSpot. Amazingly fast boot time, incredibly low RSS memory (not just heap size!) offering near instant scale up and high density memory utilization in container orchestration platforms like Kubernetes. We use a technique we call compile time boot.

It is a fourth-generation Reactive library for building non-blocking applications on the JVM based on the Reactive Streams Specification. It is a fully non-blocking foundation with efficient demand management. It directly interacts with Java functional API, Completable Future, Stream and Duration.

It is a first class persistence framework with support for custom SQL, stored procedures and advanced mappings. It eliminates almost all of the JDBC code and manual setting of parameters and retrieval of results. It can use simple XML or Annotations for configuration and map primitives, Map interfaces and Java POJOs (Plain Old Java Objects) to database records.

It is a modern server-side Java template engine for both web and standalone environments. It is aimed at creating elegant web code while adding powerful features and retaining prototyping abilities.

It is a protocol and network designed to create a content-addressable, peer-to-peer method of storing and sharing hypermedia in a distributed file system.

It is a java library that automatically plugs into your editor and build tools, spicing up your java. Never write another getter or equals method again, with one annotation your class has a fully featured builder, Automate your logging variables, and much more.

It is an extensive Java framework, which allows for the generation of type-safe queries in a syntax similar to SQL. It currently has a wide range of support for various backends through the use of separate modules including JPA, JDO, SQL, Java collections, RDF, Lucene, Hibernate Search, and MongoDB

It is used for building component-based user interfaces for web applications and was formalized as a standard through the Java Community

It is a collaborative effort created to advance blockchain technology by identifying and addressing important features and currently missing requirements. It leverages container technology to host smart contracts called “chaincode” that comprise the application logic of the system.

It enables central communication to decoupled classes with just a few lines of code – simplifying the code, removing dependencies, and speeding up app development.

It is a code generator that greatly simplifies the implementation of mappings between Java bean types based on a convention over configuration approach. The generated mapping code uses plain method invocations and thus is fast, type-safe and easy to understand.

Retrieves knowledge of the internals of the Android Framework gives it a unique ability to narrow down the cause of each leak, helping developers dramatically reduce OutOfMemoryError crashes.

It is an open source protocol which is designed to allow fast and cheap transactions.

It is a standard dependency injection framework included in Java EE 6 and higher. It allows us to manage the lifecycle of stateful components via domain-specific lifecycle contexts and inject components (services) into client objects in a type-safe way.

It is a popular open-source reporting engine. It is entirely written in Java and it is able to use data coming from any kind of data source and produce pixel-perfect documents that can be viewed, printed or exported in a variety of document formats including HTML, PDF, Excel, OpenOffice and Word.

It is designed to merge the best of two worlds: the “traditional” distributed database world and the “traditional” blockchain world. With high throughput, low latency, powerful query functionality, decentralized control, immutable data storage and built-in asset support.

It has support for common, structural tasks such as iteration and conditionals, tags for manipulating XML documents, internationalization tags, and SQL tags. It also provides a framework for integrating the existing custom tags with the JSTL tags.

It provides a rich and intuitive set of strongly-typed assertions to use for unit testing (with JUnit, TestNG or any other test framework).

It is free software that allows anyone to build their own secure, low-cost, run-anywhere applications using blockchain and smart contract technology.

It is a software which can be used to achieve Byzantine fault tolerance (BFT) in any distributed computing platforms. It consists of two chief technical components: a blockchain consensus engine and a generic application interface.

It is a peer-to-peer Internet currency that enables instant, near-zero cost payments to anyone in the world. It is an open source, global payment network that is fully decentralized without any central authorities.

It makes your Java and Android applications up to 90% smaller and up to 20% faster. It also provides minimal protection against reverse engineering by obfuscating the names of classes, fields and methods.

Generate state of the art immutable objects and builders. Type-safe, null-safe, and thread-safe, with no boilerplate. Generate builders for immutable objects and even plain static factory methods.

It is a set of Java libraries for building scalable HTTP applications. It is a lean and powerful foundation. Its apps are lightweight, fast, composable with other tools and libraries, easy to test and enjoyable to develop.

It is a platform that helps users to establish a certain private Blockchains that can be used by the organizations for financial transactions.

It is a free, simple and extensible library for checking the architecture of your Java code using any plain Java unit test framework. It can check dependencies between packages and classes, layers and slices, check for cyclic dependencies and more. It does so by analyzing given Java bytecode, importing all classes into a Java code structure.

The purpose of the Commons is to provide reusable, open source Java software. The Commons is composed of three parts: proper, sandbox, and dormant.

It is a Java library for working with real-world HTML. It provides a very convenient API for fetching URLs and extracting and manipulating data, using the best of HTML5 DOM methods and CSS selectors.

It is an open source library of graph-theoretic data structures and algorithms. It has been used in a number of university projects and classes, and shows up as a standard reference in books on Java programming.

It is a solid high-performance JDBC connection pool. It is a "zero-overhead" and production-ready JDBC connection pool. At roughly 130Kb, the library is very light.

It is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.

It is a free Java tool that calculates the percentage of code accessed by tests. It can be used to identify which parts of your Java program are lacking test coverage.

It is an implementation of Feature Toggle pattern : Enable and disable features or your applications at runtime thanks to dedicated web console, REST API, JMX or even CLI. It handle also properties and provide generic interfaces.

A library and SDK built for building decentralized web and grid computing projects.

It is a Java data access API specifically designed for the Google Cloud Datastore. It occupies a "middle ground"; easier to use and more transparent than JDO or JPA, but significantly more convenient than the low-level API libraries that Google provides. Objectify is designed to make novices immediately productive yet also expose the full power of the Datastore.

It is a leading blockchain framework, designed to bring efficiency and security to your operations.

It is the leading open-source blockchain platform that enables transparency in transactions at the speed and scale needed to solve real-world challenges.

Blockchain Infrastructure for the Decentralised Web From the Substrate blockchain framework to Polkadot, the sharded protocol enabling blockchains to operate seamlessly together at scale, Parity builds the foundation of Web 3.0.

It is a simple blockchain platform you can use to make trusted, secure, and fast applications by bringing the power of permission-based blockchain with Crash fault-tolerant consensus. It’s free, open-source, and works on Linux and Mac OS, with a variety of mobile and desktop libraries.

It implements the Java Language Specification and the Java Virtual Machine Specification and provides the Standard Edition of the Java Application Programming Interface.

It is a visual tool integrating command-line JDK tools and lightweight profiling capabilities. Designed for both development and production time use.

It is a blockchain application platform. It enables developers to make Dapps using Javascript & Typescript. The modular design of the Lisk SDK enables you to realize any kind of blockchain technology use-case.

It is remote JMX with JSON over HTTP. It is fast, simple, polyglot and has unique features.

It is based on SMPC technology and anonymous biometrics. It allows you to manage digital assets without a Private Key. It is replaced with an encrypted set of secrets, distributed between your device and professional security provider. This means that: - nobody except you has access to the funds; - your funds will still be safe even if your device is hacked; - even if you lose all credentials you can recover your wallet using your face. This makes Spatium the safest and easiest crypto wallet no matter if you haven`t heard anything about Bitcoin before, or if you are an experienced crypto geek.