USDJ is a USD-pegged stablecoin backed by collateral assets, primarily generated through decentralized smart contracts on the TRON network. It is part of the JUST DeFi ecosystem, which includes JustStable and the JustLend DAO. Here are some key ways USDJ is used:

1. Collateralized Debt Positions (CDPs): Users can pledge TRX as collateral to generate USDJ. This process involves creating a CDP, depositing the collateral, and specifying the amount of USDJ to be generated. The collateral is locked until the debt is repaid with USDJ and a stability fee in JST.

2. Price Stability Mechanism: USDJ maintains its peg to the US dollar through a Target Rate Feedback Mechanism. When the market price deviates from the target, the mechanism adjusts the Target Rate to incentivize market forces to stabilize the price. This ensures that the market price of USDJ remains close to its target value.

3. Global Settlement: In the event of market instability, a Global Settlement mechanism is triggered. This allows USDJ holders to claim their collateral assets, ensuring that the stablecoin's value is maintained.

4. Decentralized Finance (DeFi): USDJ is designed to be an integral part of the TRON DeFi ecosystem. It can be used for various DeFi applications such as lending, borrowing, and other financial services.

5. Remittances and Cross-Border Payments: USDJ can be used for fast and low-cost cross-border transfers, making it a popular choice for international remittances.

Overall, USDJ provides a stable and reliable cryptocurrency pegged to the US dollar, making it suitable for various financial applications and transactions.

To store USDJ (USDJ) tokens, you can use a reliable cryptocurrency wallet that supports the TRON network. Here are the steps to follow:

1. Download a TRON Wallet: You can download a TRON wallet from the official TRON website. There are several options available, including desktop and mobile versions. Ensure you download the official Chrome extension or mobile app to avoid any potential scams.

2. Set Up Your Wallet: Register and set up your TRON wallet using the Chrome extension or mobile app. Make sure to keep your seed phrase safe and note your wallet address, which you will need later.

3. Create a USDJ Address: Once your wallet is set up, you can create a USDJ address. This address will be used to receive and manage your USDJ tokens. You can use a wallet like Noone Wallet, which allows you to create a USDJ address and manage your tokens easily.

By following these steps, you can securely store your USDJ tokens in a TRON-compatible wallet.

To buy USDJ tokens, follow these steps:

1. Choose a Reliable Exchange: Find a trusted centralized exchange that lists USDJ. You can refer to CoinMarketCap's Markets section to find the list of exchanges where USDJ is available. Some popular options include MEXC and other exchanges that support the TRON network.

2. Set Up a Wallet: Download a TRON wallet, such as the Tron Wallet Chrome extension or the mobile app. Ensure you download the official version from the Tron website. Set up your wallet by registering and keeping your seed phrase safe.

3. Buy TRON as Base Currency: If you don't already have TRON, purchase it on an exchange like Binance. Then, transfer the TRON to your TRON wallet.

4. Select a Decentralized Exchange (DEX): Choose a DEX that supports the TRON network and your wallet. For example, you can use SunSwap if you have a Tron wallet.

5. Connect Your Wallet: Connect your TRON wallet to the chosen DEX using your wallet address.

6. Trade TRON for USDJ: Select TRON as the payment and USDJ as the coin you want to buy. If USDJ doesn't appear, find its smart contract address on a site like trx.tokenview.com and paste it into the DEX.

7. Complete the Swap: Confirm the transaction details and click the "Swap" button to complete the purchase.

Alternatively, you can also buy USDJ directly on MEXC by opening an account, passing KYC, and using various payment methods like credit cards or bank transfers.