while(true) loop without break

Question

I am quite new to Java programming. For now I am studying source code of an android app called Evercam. However, I have a problem understanding a part of the code which involves while(true) loop.

Here is the snippet of the code:

while (true)
{
    while (true)
    {
        byte[] responseMessageByteArray = new byte[4000];
        DatagramPacket datagramPacketRecieve = new DatagramPacket(responseMessageByteArray, responseMessageByteArray.length);
        datagramSocket.receive(datagramPacketRecieve);
        String responseMessage = new String(datagramPacketRecieve.getData());
        EvercamDiscover.printLogMessage("\nResponse Message:\n" + responseMessage);
        StringReader stringReader = new StringReader(responseMessage);
        InputNode localInputNode = NodeBuilder.read(stringReader);
        EnvelopeProbeMatches localEnvelopeProbeMatches = (EnvelopeProbeMatches)(new Persister()).read(EnvelopeProbeMatches.class, localInputNode);
        if (localEnvelopeProbeMatches.BodyProbeMatches.ProbeMatches.listProbeMatches.size() > 0)
        {
            ProbeMatch localProbeMatch = (ProbeMatch) localEnvelopeProbeMatches.BodyProbeMatches.ProbeMatches.listProbeMatches.get(0);
            if (uuidArrayList.contains(localProbeMatch.EndpointReference.Address))
            {
                EvercamDiscover.printLogMessage("ONVIFDiscovery: Address " + localProbeMatch.EndpointReference.Address + " already added");
            }
            else
            {
                uuidArrayList.add(localProbeMatch.EndpointReference.Address);
                DiscoveredCamera discoveredCamera = getCameraFromProbeMatch(localProbeMatch);
                if (discoveredCamera.hasValidIpv4Address())
                {
                    this.onActiveOnvifDevice(discoveredCamera);
                    cameraList.add(discoveredCamera);
                }
            }
        }
    }
}

Doesn't this create an infinite loop? My fundamentals in Java isn't strong, so I would be so grateful if anyone can tell in in what instances will a while(true){//codes} actually exits without any break or does it ever exit??

---

EDIT

My bad for actually extracting this snippet from decompiling directly from the android project files. I did not know that it would be different, and then again, I know very little. Here is the original code:

    public ArrayList<DiscoveredCamera> probe() {
ArrayList<DiscoveredCamera> cameraList = new ArrayList<DiscoveredCamera>();

try {
    DatagramSocket datagramSocket = new DatagramSocket();
    datagramSocket.setSoTimeout(SOCKET_TIMEOUT);
    InetAddress multicastAddress = InetAddress.getByName(PROBE_IP);

    if (multicastAddress == null) {
    // System.out.println("InetAddress.getByName() for multicast returns null");
    return cameraList;
    }

    // Send the UDP probe message
    String soapMessage = getProbeSoapMessage();
    // System.out.println(soapMessage);
    byte[] soapMessageByteArray = soapMessage.getBytes();
    DatagramPacket datagramPacketSend = new DatagramPacket(
        soapMessageByteArray, soapMessageByteArray.length,
        multicastAddress, PROBE_PORT);
    datagramSocket.send(datagramPacketSend);

    ArrayList<String> uuidArrayList = new ArrayList<String>();
    while (true) {
    // System.out.println("Receiving...");
    byte[] responseMessageByteArray = new byte[4000];
    DatagramPacket datagramPacketRecieve = new DatagramPacket(
        responseMessageByteArray,
        responseMessageByteArray.length);
    datagramSocket.receive(datagramPacketRecieve);

    String responseMessage = new String(
        datagramPacketRecieve.getData());

    EvercamDiscover.printLogMessage("\nResponse Message:\n"
        + responseMessage);

    StringReader stringReader = new StringReader(responseMessage);
    InputNode localInputNode = NodeBuilder.read(stringReader);
    EnvelopeProbeMatches localEnvelopeProbeMatches = new Persister()
        .read(EnvelopeProbeMatches.class, localInputNode);
    if (localEnvelopeProbeMatches.BodyProbeMatches.ProbeMatches.listProbeMatches
        .size() <= 0) {
        continue;
    }

    ProbeMatch localProbeMatch = localEnvelopeProbeMatches.BodyProbeMatches.ProbeMatches.listProbeMatches
        .get(0);
    // EvercamDiscover.printLogMessage("Probe matches with UUID:\n"
    // +
    // localProbeMatch.EndpointReference.Address + " URL: " +
    // localProbeMatch.XAddrs);
    if (uuidArrayList
        .contains(localProbeMatch.EndpointReference.Address)) {
        EvercamDiscover.printLogMessage("ONVIFDiscovery: Address "
            + localProbeMatch.EndpointReference.Address
            + " already added");
        continue;
    }
    uuidArrayList.add(localProbeMatch.EndpointReference.Address);
    DiscoveredCamera discoveredCamera = getCameraFromProbeMatch(localProbeMatch);

    if (discoveredCamera.hasValidIpv4Address()) {
        onActiveOnvifDevice(discoveredCamera);
        cameraList.add(discoveredCamera);
    }
    }
} catch (Exception e) {
    // ONVIF timeout. Don't print anything.
}

Turns out there is continue statement in the actual code. Thank you so much for the response, I will remember that de-compiled classes should not be depended on.

Answer 1

This looks like an infinite loop. To be absolutely sure, you would have to statically read every statement and follow invoked methods to see if any possible invocations like Activity#finish() or Service#stopSelf() exists which would finish the currently running activity, effectively breaking the loop.

Another possibility is that the code is intended to be running in an infinite loop as a background thread service, and some other component would have an option to kill that service when it reaches a certain condition. For example, it could be part of a Runnable class and executed in a thread pool, and when a timeout exists, the pool is shut down.