Web3j is a highly modular, reactive, type safe Java and Android library for working with smart contracts and integrating with clients (nodes) on the Ethereum network. This allows you to work with the Ethereum blockchain, without the additional overhead of having to write your own integration code for the platform.
Web3j provides the following capabilities:
- Complete implementation of Ethereum's JSON-RPC client API over HTTP and IPC
- Auto-generation of Java smart contract wrappers to create, deploy, transact with and call smart contracts from native Java code
- Type safe mappings from native EVM types to JVM and OpenAPI
- Robust testing capabilities — embedded production -EVM and flexible integration testing capabilities via containers
- Transaction: Supports EIP 155, EIP 1559, EIP 2930, EIP 4844 
- Supports all EVM based blockchains and Appchains like Polygon, Linea, Optimism, Base.
- Node API support including Geth and Besu specific API and privacy support (sole implementation of this)
- Support for HSM (Hardware Security Modules)
- Full Android compatibility
- Solidity compiler installation and management integrated with build tools
- Ethereum Name Service (ENS) support
- Command line Interface - 
  - New project creation - Basic Boilerplate Web3j project, ERC20, ERC721
  - Project creation from existing Solidity code
  - Smart Contract compilation
  - Wallet creation and password management
