Use DescribeLogStreams with an AWS SDK or CLI

The following command shows all log streams starting with the prefix 2015 in the log group my-logs:

aws logs describe-log-streams --log-group-name my-logs --log-stream-name-prefix 2015

Output:

{
    "logStreams": [
        {
            "creationTime": 1433189871774,
            "arn": "arn:aws:logs:us-west-2:0123456789012:log-group:my-logs:log-stream:20150531",
            "logStreamName": "20150531",
            "storedBytes": 0
        },
        {
            "creationTime": 1433189873898,
            "arn": "arn:aws:logs:us-west-2:0123456789012:log-group:my-logs:log-stream:20150601",
            "logStreamName": "20150601",
            "storedBytes": 0
        }
    ]
}

Searches for log streams within a specified log group that match a given prefix.

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 * <p>
 * For more information, see the following documentation topic:
 * <p>
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class CloudWatchLogsSearch {

    public static void main(String[] args) {
        final String usage = """

                Usage:
                  <logGroupName> <logStreamName> 

                Where:
                  logGroupName - The name of the log group (for example, WeathertopJavaContainerLogs).
                  logStreamName - The name of the log stream (for example, weathertop-java-stream).
                  pattern - the pattern to use (for example, INFO) 
                  
                """;

        if (args.length != 3) {
            System.out.print(usage);
            System.exit(1);
        }

        String logGroupName = args[0] ;
        String logStreamName = args[1] ;
        String pattern = args[2] ;

        CloudWatchLogsClient cwlClient = CloudWatchLogsClient.builder()
                .region(Region.US_EAST_1)
                .build();

        searchLogStreamsAndFilterEvents(cwlClient, logGroupName, logStreamName, pattern);
    }

    /**
     * Searches for log streams with a specific prefix within a log group and filters log events based on a specified pattern.
     *
     * @param cwlClient       the CloudWatchLogsClient used to interact with AWS CloudWatch Logs
     * @param logGroupName    the name of the log group to search within
     * @param logStreamPrefix the prefix of the log streams to search for
     * @param pattern         the pattern to filter log events by
     */
    public static void searchLogStreamsAndFilterEvents(CloudWatchLogsClient cwlClient, String logGroupName, String logStreamPrefix, String pattern) {
        DescribeLogStreamsRequest describeLogStreamsRequest = DescribeLogStreamsRequest.builder()
                .logGroupName(logGroupName)
                .logStreamNamePrefix(logStreamPrefix)
                .build();

        DescribeLogStreamsResponse describeLogStreamsResponse = cwlClient.describeLogStreams(describeLogStreamsRequest);
        List<LogStream> logStreams = describeLogStreamsResponse.logStreams();

        for (LogStream logStream : logStreams) {
            String logStreamName = logStream.logStreamName();
            System.out.println("Searching in log stream: " + logStreamName);

            FilterLogEventsRequest filterLogEventsRequest = FilterLogEventsRequest.builder()
                    .logGroupName(logGroupName)
                    .logStreamNames(logStreamName)
                    .filterPattern(pattern)
                    .build();

            FilterLogEventsResponse filterLogEventsResponse = cwlClient.filterLogEvents(filterLogEventsRequest);

            for (FilteredLogEvent event : filterLogEventsResponse.events()) {
                System.out.println(event.message());
            }

            System.out.println("--------------------------------------------------"); // Separator for better readability
        }
    }
}

Prints metadata about the most recent log stream in a specified log group.

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 * <p>
 * For more information, see the following documentation topic:
 * <p>
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class CloudWatchLogQuery {
    public static void main(final String[] args) {
        final String usage = """
                Usage:
                  <logGroupName>

                Where:
                  logGroupName - The name of the log group (for example, /aws/lambda/ChatAIHandler).
                """;

        if (args.length != 1) {
            System.out.print(usage);
            System.exit(1);
        }

        String logGroupName = "/aws/lambda/ChatAIHandler" ; //args[0];
        CloudWatchLogsClient logsClient = CloudWatchLogsClient.builder()
                .region(Region.US_EAST_1)
                .build();

        describeMostRecentLogStream(logsClient, logGroupName);
    }

    /**
     * Describes and prints metadata about the most recent log stream in the specified log group.
     *
     * @param logsClient   the CloudWatchLogsClient used to interact with AWS CloudWatch Logs
     * @param logGroupName the name of the log group
     */
    public static void describeMostRecentLogStream(CloudWatchLogsClient logsClient, String logGroupName) {
        DescribeLogStreamsRequest streamsRequest = DescribeLogStreamsRequest.builder()
                .logGroupName(logGroupName)
                .orderBy(OrderBy.LAST_EVENT_TIME)
                .descending(true)
                .limit(1)
                .build();

        try {
            DescribeLogStreamsResponse streamsResponse = logsClient.describeLogStreams(streamsRequest);
            List<LogStream> logStreams = streamsResponse.logStreams();

            if (logStreams.isEmpty()) {
                System.out.println("No log streams found for log group: " + logGroupName);
                return;
            }

            LogStream stream = logStreams.get(0);
            System.out.println("Most Recent Log Stream:");
            System.out.println("  Name: " + stream.logStreamName());
            System.out.println("  ARN: " + stream.arn());
            System.out.println("  Creation Time: " + stream.creationTime());
            System.out.println("  First Event Time: " + stream.firstEventTimestamp());
            System.out.println("  Last Event Time: " + stream.lastEventTimestamp());
            System.out.println("  Stored Bytes: " + stream.storedBytes());
            System.out.println("  Upload Sequence Token: " + stream.uploadSequenceToken());

        } catch (CloudWatchLogsException e) {
            System.err.println("Failed to describe log stream: " + e.awsErrorDetails().errorMessage());
        }
    }
}