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IBM Blockchain Foundation Developer Cognitive Class Exam Answers

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IBM Blockchain Foundation Developer Cognitive

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Question 1: A developer has installed the IBM Blockchain Platform VS Code extension but cannot see the Fabric Environments, Smart Contracts, Fabric Wallets and Fabric Gateways views. Where should they click?

  • the IBM Blockchain Platform icon in the VS Code activity bar
  • the ‘View homepage’ icon
  • the Smart Contract project in the Explorer view
  • the ‘IBM Blockchain Platform’ extension in the Extensions Marketplace

Question 2: How can a developer quickly show all the available commands implemented by the IBM Blockchain Platform extension?

  • Click the “Tutorials” link from the extension homepage.
  • From the VS Code main menu, click “View” -> “IBM Blockchain Platform”.
  • Right-click the IBM Blockchain Platform icon in the activity bar.
  • Click “View” -> “Command Palette” and enter “>IBM Blockchain Platform”.

Question 3: Which of the following is a deterministic value for a smart contract to calculate and store in the world state?

  • the n’th digit of pi, where n is supplied as an input parameter to the transaction
  • the number of milliseconds since 00:00 1 January 1970
  • a random number between 1 and 1000
  • the DHCP address of the peer running the smart contract

Question 4: A transaction’s signature in a Hyperledger Fabric TypeScript smart contract is decorated with “@Transaction(false)”. What does this mean?

  • This transaction should be hidden from the list of transactions that this smart contract exposes.
  • This transaction should be exposed as a read-only transaction.
  • This transaction should be exposed as a transaction that takes no parameters.
  • This transaction should be exposed as a transaction that has no module dependencies.

Question 5: A developer is using the IBM Blockchain Platform VS Code extension to create a skeleton TypeScript smart contract project, which will be instantiated as “DemoContract@0.0.1”. From where is this name and version derived?

  • the name of the enclosing project folder
  • the smart contract Typescript source file name
  • the file ‘tsconfig.json’
  • the file ‘package.json’

Question 6: In the Fabric Environments view of the IBM Blockchain Platform VS Code extension, a smart contract is listed under “Installed” but not under “Instantiated”. What does this mean for the smart contract?

  • It has been started but no transactions have been run.
  • It probably contains compilation errors.
  • It has been built but not packaged.
  • It has been copied to the peer(s) but not started.

Question 7: Which view in the IBM Blockchain Platform VS Code extension shows a single connection to a Hyperledger Fabric network using a supplied identity?

  • Fabric Gateways
  • Fabric Environments
  • Smart Contracts
  • Fabric Wallets

Question 8: In Hyperledger Fabric, what is the difference between a submitted transaction and an evaluated transaction?

  • Submitted transactions are recorded on the blockchain ledger; evaluated transactions are not.
  • Submitted transactions take place on a single peer; evaluated transactions run across multiple peers.
  • Submitted transactions run in real-time; evaluated transactions are batched.
  • Submitted transactions are called on behalf of another organization; evaluated transactions are not.

Question 9: In order to connect a standalone application to the Hyperledger Fabric instance embedded in the IBM Blockchain Platform VS Code extension, which of the following must be exported?

  • Ordering Service
  • Connection Profile
  • Fabric Environment
  • Smart Contract

Question 10: A developer is writing a standalone TypeScript application to submit a transaction to a Hyperledger Fabric network. Against which object is the submitTransaction method called?

  • wallet
  • contract
  • network
  • gateway

Question 11: A developer is using the IBM Blockchain Platform VS Code extension to upgrade the version of a smart contract running on an instance of Hyperledger Fabric V1.x.  What will happen to the old version of the smart contract when they do this?

  • The old version of the smart contract will no longer be listed as instantiated.
  • The old version of the smart contract will be uninstalled from the peer.
  • The old version of the smart contract will be removed from the Smart Contracts view.
  • The old version of the smart contract will be installed to a backup channel.

Question 12: A developer has used the IBM Blockchain Platform VS Code extension to make a change to a smart contract and its version identifier. Typically, what will they then do in the Smart Contracts view to package the modified smart contract so that the new version appears there?

  • Delete the old smart contract package; this causes an automatic repackaging.
  • Select the old smart contract and drag it onto the Package icon.
  • Click the ellipsis (‘…’) and select the “Package Open Project” option.
  • Right-click the old package and select the “Upgrade Smart Contract” option.

Question 13: When using the IBM Blockchain Platform VS Code extension, which of the following tasks can be done directly in the debug bar of the VS Code debugger?

  • execute a transaction
  • query the block height
  • endorse a transaction
  • start a peer

Question 14: How does a developer know that a smart contract is under an active debug session in the IBM Blockchain Platform VS Code extension?

  • The VS Code debug side bar is visible.
  • The status bar at the bottom of the screen is a different color, and shows the text “Debug Smart Contract”.
  • The smart contract source file will have a breakpoint indicator.
  • The IBM Blockchain Platform icon in the activity bar has a red notification decorator.

Question 15: For which object in the IBM Blockchain Platform VS Code extension can tests be generated?

  • channel
  • smart contract
  • peer
  • wallet

Question 16: Assuming an otherwise working environment, what is the most likely result of running a functional test that has been generated by the IBM Blockchain Platform VS Code extension, but that has not yet been customized?

  • The test will complete and pass.
  • The test will complete with an error message.
  • The test will prompt for input parameters.
  • The test will not compile.

Question 17: What two pieces of information are supplied by the smart contract when emitting an event?

  • the transaction name and input parameters
  • the smart contract name and endorsement policy
  • the read set and the write set
  • the topic name and payload

Question 18: A developer uses the “Subscribe to Events” feature in the IBM Blockchain Platform VS Code extension. For how long does the subscription persist?

  • until the next block is committed
  • until the first event is triggered
  • until the gateway is disconnected
  • until the developer selects the “Unsubscribe from Events” option

Question 19: In a Hyperledger Fabric-based network, which of the following are responsible for executing smart contract code?

  • client applications
  • all peers on the channel
  • ordering service nodes
  • endorsing peers

Question 20: Three organizations use Hyperledger Fabric to share transaction data. They each connect to the same single peer that is run by a network service provider, and identify themselves to each other using certificates provided by a shared certificate authority. What is a problem with this scenario?

  • there is a single point of trust
  • only one smart contract can be deployed
  • new members cannot join the network
  • each organization must use the same client application

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