/technologies/internet-of-things/b/blog/posts/blockchain---analyse-the-infineon-android-demo-app---part-b-retrieve-ethereum-crypto-currency-balanceThis post is part of the Infineon Blockchain Starter Kit road test. Blockchain - outside of the bitcoin context - is new to me. Follow along with me on this path to learn the technology.... Let&#39;s dive further into the example Androi...en-USTelligent Community 12https://community.element14.com/technologies/internet-of-things/b/blog/posts/blockchain---analyse-the-infineon-android-demo-app---part-b-retrieve-ethereum-crypto-currency-balanceSat, 21 Mar 2020 17:46:39 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:b8f58816-fbc5-4663-9e4d-d5ab6595640bJan Cumps0<blockquote class="jive-quote"><p>The <span style="font-weight:inherit;font-style:inherit;">EthereumUtils</span> class is the one that will call web3j.</p><p>The <span style="font-weight:inherit;font-style:inherit;">UiUtils</span> class holds the URL for us. For the Ropsten network, this is <a class="" href="https://ropsten.infura.io/v3/7b40d72779e541a498cb0da69aa418a2" style="font-weight:inherit;font-style:inherit;" title="https://ropsten.infura.io/v3/7b40d72779e541a498cb0da69aa418a2">https://ropsten.infura.io/v3/7b40d72779e541a498cb0da69aa418a2</a></p><p>This URL is built out of constants. I do not know what the <span style="font-weight:inherit;font-style:inherit;">7b40d72779e541a498cb0da69aa418a2</span> value means.</p></blockquote><p>&nbsp;</p><p>The magical value turns out to be a project ID. See <a class="jive-link-external-small" href="https://infura.io/docs/gettingStarted/makeRequests.md" rel="nofollow ugc noopener" target="_blank" title="https://infura.io/docs/gettingStarted/makeRequests.md">https://infura.io/docs/gettingStarted/makeRequests.md</a></p><p><span style="text-decoration:line-through;">I don&#39;t know how to define or find that yet, but at least</span> it isn&#39;t a magic number anymore. It has a meaning.</p><p>&nbsp;</p><p>edit - you get the project id when signing up: <a class="jive-link-external-small" href="https://infura.io/docs" rel="nofollow ugc noopener" target="_blank" title="https://infura.io/docs">https://infura.io/docs</a> </p><img src="https://community.element14.com/aggbug?PostID=8865&AppID=27&AppType=Weblog&ContentType=0" width="1" height="1">