Mention Android for PolkaJ (w3f#649)

docs/polkadot_stack.md

@@ -85,7 +85,7 @@ In the below sections you can find a list of different layers of the Polkadot St
 | Components | Existing projects | Potentially interesting projects
 |-|-|-
 | Parachain Dev Kits | [Gantree](https://github.com/flex-dapps)| [Minimal Parachain Dev Kit](https://github.com/w3f/General-Grants-Program/issues/204), tools to create parachains from frameworks used in other ecosystems |
-| Client Libraries | [Go](https://github.com/centrifuge/go-substrate-rpc-client), [.Net](https://github.com/usetech-llc/polkadot_api_dotnet), [.NET Standard 2.0](https://github.com/dotmog/SubstrateNetApi), [C++](https://github.com/usetech-llc/polkadot_api_cpp), [C](https://github.com/finoabanking/substrate-c-tool), [Haskell](https://github.com/airalab/hs-web3), [Javascript](https://github.com/polkadot-js/api), [Substrate API Sidecar - TypeScript](https://github.com/paritytech/substrate-api-sidecar), [Ruby](https://github.com/itering/scale.rb), [Python](https://github.com/polkascan/substrate-interface-api), [Java](https://github.com/polkadot-java)*(old)*, [Java](https://github.com/emeraldpay/polkaj)*(new)*, [Rust SCS](https://github.com/scs/substrate-api-client), [Rust Parity](https://github.com/paritytech/substrate-subxt), [PHP](https://github.com/gmajor-encrypt/php-substrate-api), [RPC-Ethereum](https://github.com/paritytech/frontier), [Swift](https://github.com/tesseract-one/Substrate.swift) | |
+| Client Libraries | [Go](https://github.com/centrifuge/go-substrate-rpc-client), [.Net](https://github.com/usetech-llc/polkadot_api_dotnet), [.NET Standard 2.0](https://github.com/dotmog/SubstrateNetApi), [C++](https://github.com/usetech-llc/polkadot_api_cpp), [C](https://github.com/finoabanking/substrate-c-tool), [Haskell](https://github.com/airalab/hs-web3), [Javascript](https://github.com/polkadot-js/api), [Substrate API Sidecar - TypeScript](https://github.com/paritytech/substrate-api-sidecar), [Ruby](https://github.com/itering/scale.rb), [Python](https://github.com/polkascan/substrate-interface-api), [Java](https://github.com/polkadot-java)*(old)*, [Java (+ Android)](https://github.com/emeraldpay/polkaj)*(new)*, [Rust SCS](https://github.com/scs/substrate-api-client), [Rust Parity](https://github.com/paritytech/substrate-subxt), [PHP](https://github.com/gmajor-encrypt/php-substrate-api), [RPC-Ethereum](https://github.com/paritytech/frontier), [Swift](https://github.com/tesseract-one/Substrate.swift) | |
 |Substrate Contract clients | [PatractGo](https://github.com/patractlabs/go-patract)  | |
 | SCALE Codec | [Rust](https://github.com/paritytech/parity-scale-codec), [Python](https://github.com/polkascan/py-scale-codec), [Golang Chainsafe](https://github.com/ChainSafe/gossamer/tree/development/lib/scale), [Golang Itering](https://github.com/itering/scale.go), [C++](https://github.com/soramitsu/kagome/tree/master/core/scale), [JavaScript](https://github.com/polkadot-js/api), [AssemblyScript](https://github.com/LimeChain/as-scale-codec), [Haskell](https://github.com/airalab/hs-web3/tree/master/src/Codec), [Java](https://github.com/emeraldpay/polkaj), [Ruby](https://github.com/itering/scale.rb), [Dart](https://github.com/nbltrust/dart-scale-codec), [Swift](https://github.com/tesseract-one/swift-scale-codec), [PHP](https://github.com/gmajor-encrypt/php-scale-codec) |
 | Easy Runtime Development | [VS Code Plugin](https://github.com/everstake/vscode-plugin-substrate), [Atom Code Plugin](https://github.com/everstake/atom-plugin-substrate), [Substrate Playground](https://github.com/paritytech/substrate-playground), [Substrate Marketplace VS Code Plugin](https://github.com/paritytech/vscode-substrate), [AssemblyScript Runtime Generation](https://github.com/LimeChain/as-substrate-runtime), [Substrate Package Manager](https://github.com/clearloop/sup), [Subsembly: Framework for developing AssemblyScript Substrate Runtimes](https://github.com/LimeChain/subsembly), [dependency diener](https://github.com/bkchr/diener) | |