How would you use InetAddress to perform DNS resolution (converting a hostname to an IP address) programmatically, and what's the difference between InetAddress.getByName() and getAllByName()?

InetAddress.getByName(hostname) resolves a hostname to a single IP address (returning the first one found if a hostname resolves to multiple addresses, common for load-balanced services), while getAllByName(hostname) returns an array of ALL IP addresses that hostname currently resolves to, useful for implementing custom client-side load balancing or failover logic across multiple backend IPs -- both perform an actual DNS lookup (a network operation, meaning it can throw UnknownHostException if resolution fails, and involves genuine latency, so results are often worth caching briefly rather than re-resolving on every single use).

try {
    InetAddress address = InetAddress.getByName("example.com");
    System.out.println(address.getHostAddress());  // e.g. "93.184.216.34"

    InetAddress[] allAddresses = InetAddress.getAllByName("example.com");
    for (InetAddress addr : allAddresses) {
        System.out.println(addr.getHostAddress());  // could print multiple IPs for a load-balanced service
    }
} catch (UnknownHostException e) {
    System.err.println("DNS resolution failed: " + e.getMessage());
}