Help me to understand with this Java

Ethereum Blocks A blockchain is a database of transactions that is updated and shared across many computers in a network. Every time a new set of transactions is added, it's called a "block" - hence the name blockchain. Most blockchains are public, and you can only add data, not remove. If someone wanted to alter any of the information or cheat the system, they'd need to do so on the majority of computers on the network. For this project, we will be using a dataset of 100 blocks in the Ethereum blockchain. You will be updating your Blocks.java class to accomplish the tasks laid out by the Project 2 pdf and Driver.java. Updated Blocks UML Blocks -number: int -miner: String -timestamp: long -transactions: int -blocks: ArrayList +Blocks() +Blocks(number: int) +Blocks(number: int, miner: String) +Blocks(number: int, miner: String, timestamp: long, transactions: int) +getNumber(): int +getMiner(): String +getTransactions(): int +getDate(): String +getBlocks(): ArrayList +calUniqMiners(): void +blockDiff(A: Blocks, B: Blocks): int +getBlockByNumber(num: int): Blocks +toString(): String +readFile(filename: String): void +sortBlocksByNumber(): void +timeDiff(first: Blocks, second: Blocks): void +transactionDiff(first: Blocks, second: Blocks): int Feel free to add your own helper methods as needed. Methods Read File You will need to update your readFile() method to read in the two new fields, timestamp and transaction_count. They are columns 17 and 18 respectively in the data file.