Web3j-evm is an embedded freestanding Ethereum EVM and ledger running within a Java process, which can be used for unit and integration testing your Web3j projects.
As everything is local and in-process, there is no need to start up external Ethereum nodes, which helps with easy of use and performance.
Everything runs within the JVM process, including EVM bytecode, which allows for easy debugging of Solidity smart contracts.
Often you'd use this together with the web3j-unit project, allowing you to run unit and integration tests without the need to start an Ethereum node.
If you want to use this within our own project directly, you would need the EVM dependency + a few external libraries. Have a look at the example project on how to do this.
repositories {
mavenCentral()
}
dependencies {
implementation "org.web3j:core:4.12.2"
implementation "org.web3j:web3j-evm:4.12.2"
}Below is a simple demonstration of ETH transactions, contract deployment and simple contract interactions. Using the ConsoleDebugTracer, we're able to step through the EVM bytecode, inspect the stack and also see where in the related solidity code we're currently at.
The demo also show to how get started with the EmbeddedWeb3jService
which is what you'd use when building your web3j instance.
This demo is available on the example project.
