Java

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• cloning Java objects
• creating a proxy objects
• speeding up EJB lookups
• ZIP compressing in Java
• writing a JUnit testcase
• serializing Java objects
• using Java logger
• looking up hostnames by IP in Java
• implementing a Queue in Java
• parsing XML files (DOM)
• reading files in java

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How to look up hostname in Java

This example shows how to look up hostnames in Java.

import java.net.InetAddress;
import java.net.UnknownHostException;

class HostLookup {
    public static String lookupHostName(String ip) {
        String hostName = ip;
        try {
            InetAddress addr = InetAddress.getByName(ip);
            hostName = addr.getHostName();

        } catch (UnknownHostException e) {
        }
        return hostName;
    }

    public static String lookupCanonicalHostName(String ip) {
        String hostName = ip;
        try {
            InetAddress addr = InetAddress.getByName(ip);
            hostName = addr.getCanonicalHostName();
        } catch (UnknownHostException e) {
        }
        return hostName;
    }
}