Understanding Null, Empty List, and Empty Array in Java
As a programmer, it’s essential to differentiate between null, empty lists, and empty arrays when working in Java. Here’s a quick breakdown from my experience:
- Null: It means the reference points to nothing. Accessing it will lead to a NullPointerException. - Empty List: A list that has been initialized but contains no elements, for example:
List<String> list = new ArrayList<>();
- Empty Array: An array that has been initialized with a specific length but contains no values:
String[] array = new String[0];
To avoid confusion, remember that an empty list and an empty array are still objects, hence they can be instantiated, while null is not.
When converting between these types, try to ensure that you're handling potential null values properly to avoid exceptions. It's advisable to always check and fill lists or arrays as needed.
Keep these distinctions in mind to avoid pitfalls in your code! 🚀
Understanding Null, Empty List, and Empty Array in Java
As a programmer, it’s essential to differentiate between null, empty lists, and empty arrays when working in Java. Here’s a quick breakdown from my experience:
- Null: It means the reference points to nothing. Accessing it will lead to a NullPointerException. - Empty List: A list that has been initialized but contains no elements, for example:
List<String> list = new ArrayList<>();
- Empty Array: An array that has been initialized with a specific length but contains no values:
String[] array = new String[0];
To avoid confusion, remember that an empty list and an empty array are still objects, hence they can be instantiated, while null is not.
When converting between these types, try to ensure that you're handling potential null values properly to avoid exceptions. It's advisable to always check and fill lists or arrays as needed.
Keep these distinctions in mind to avoid pitfalls in your code! 🚀
BY Top Java Quiz Questions ☕️
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n the U.S. people generally use Bitcoin as an alternative investment, helping diversify a portfolio apart from stocks and bonds. You can also use Bitcoin to make purchases, but the number of vendors that accept the cryptocurrency is still limited. Big companies that accept Bitcoin include Overstock, AT&T and Twitch. You may also find that some small local retailers or certain websites take Bitcoin, but you’ll have to do some digging. That said, PayPal has announced that it will enable cryptocurrency as a funding source for purchases this year, financing purchases by automatically converting crypto holdings to fiat currency for users. “They have 346 million users and they’re connected to 26 million merchants,” says Spencer Montgomery, founder of Uinta Crypto Consulting. “It’s huge.”
How to Buy Bitcoin?
Most people buy Bitcoin via exchanges, such as Coinbase. Exchanges allow you to buy, sell and hold cryptocurrency, and setting up an account is similar to opening a brokerage account—you’ll need to verify your identity and provide some kind of funding source, such as a bank account or debit card. Major exchanges include Coinbase, Kraken, and Gemini. You can also buy Bitcoin at a broker like Robinhood. Regardless of where you buy your Bitcoin, you’ll need a digital wallet in which to store it. This might be what’s called a hot wallet or a cold wallet. A hot wallet (also called an online wallet) is stored by an exchange or a provider in the cloud. Providers of online wallets include Exodus, Electrum and Mycelium. A cold wallet (or mobile wallet) is an offline device used to store Bitcoin and is not connected to the Internet. Some mobile wallet options include Trezor and Ledger.
