Ron McLeod

Unrelated to the DB question - but if you need a solid tool to verify/refresh/repair media on spinning and solid-state drives, I recommend SpinRite from Gibson Research Corporation.  I have been using it for over 20 years in a commercial IT environment and it has repeatedly saved our butts.

It is not freeware.  The cost is around $90USD, and if used in a commercial or enterprise environment, the author suggests that you buy 5 copies.

If you need a SQL database then Derby or SQLite are probably good choices.  SQLite only runs as embedded (not client-server), and Derby has a driver which allows it to run as embedded.

But since it sounds like your application with be single-user with no concurrency, maybe a key-value store type solution using Java Collections which gets serialized to/from the file system (using JSON/YAML/etc) might be good enough.  It really depends what you are going to be doing with the data, how frequently it changes, how much time you can bear to serialize/deserialize during startup/shutdown, whether the data need to be flushed to the file  system on change and/or periodically, how often the application would be restarted, etc.

Right.  The example that I provided only has one class which could be used to show either evens or odds, depending on what was specified when the instance was created.

Would something like this do what you are wanting?:public class Sample {    public static void main(String[] args) {        Multitasking e = new Multitasking(true);        Multitasking o = new Multitasking(false);        e.start();        o.start();    } } class Multitasking extends Thread {    boolean showEvens;    Multitasking(boolean showEvens) {        this.showEvens = showEvens;    }    private void even() {        for (int i = 0; i < 10; i++) {            if (i % 2 == 0) {                System.out.print(i + " ");            }        }    }    private void odd() {        for (int i = 0; i < 10; i++) {            if (i % 2 != 0) {                System.out.print(i + " ");            }        }    }    @Override    public void run() {        if (showEvens) {            even();        } else {            odd();        }    } }

The link on Scott's website is for Singapore (not sure why).

For Canada, use this link:
     https://www.wiley.com/en-ca/OCP+Oracle+Certified+Professional+Java+SE+21+Developer+Study+Guide-p-9781394286614

At check-out, the country will be set to Canada:

Swapnil Mishra wrote:I want to concurrently add and remove elements to a TreeSet..

Are you modifying the collection concurrently using multiple threads, or trying to make changes while iterating through the elements?

I looked at this a bit more, and found that there are two ways (maybe more) to resolve the host key issue.

Both require that you get the ssh key for the host - for example:ssh-keyscan -t ed25519 172.25.161.106 # 172.25.161.106:22 SSH-2.0-OpenSSH_8.0 172.25.161.106 ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIEBGCmkQ0C9kV1ExIfK9U5dXcOmTiyu9gkQ2jz4hE+xn
Method 1:
   - Add the key information to your local host's known_hosts file
   - tell Jsch the location of the file:JSch jsch = new JSch(); String knownHostsPath = System.getProperty("user.home") + "\\.ssh\\known_hosts"; jsch.setKnownHosts(knownHostsPath); Session session = jsch.getSession(user, host, port); session.setPassword(pass); session.connect();

Method 2:
   - add the key information at on the fly:JSch jsch = new JSch(); addKey(jsch); Session session = jsch.getSession(user, host, port); session.setPassword(pass); session.connect(); ... void addKey(JSch jsch) throws JSchException {    String host = "172.25.161.106";    String key = "AAAAC3NzaC1lZDI1NTE5AAAAIEBGCmkQ0C9kV1ExIfK9U5dXcOmTiyu9gkQ2jz4hE+xn";    byte[] keyBytes = Base64.getDecoder().decode(key);    HostKeyRepository hkr = jsch.getHostKeyRepository();    HostKey hostKey = new HostKey(host, HostKey.ED25519, keyBytes);    hkr.add(hostKey, null); }

I hope this helps.

I haven't spent too long looking at this, but it seems like the problem is that Jsch is not able to find the host key in its repository.

For testing, you can bypass this check, by setting StrictHostKeyChecking to no (probably not a good idea when running in an production environment).

It gave it a quick try, and was able to establish a connection and perform an ls on the remote host:import com.jcraft.jsch.Channel; import com.jcraft.jsch.ChannelSftp; import com.jcraft.jsch.JSch; import com.jcraft.jsch.JSchException; import com.jcraft.jsch.Session; import com.jcraft.jsch.SftpException; public class SftpTest {    @Test    public void test_sftp() throws JSchException, SftpException {        String user = "******";        String pass = "******";        String host = "172.25.161.106";        int port = 22;        JSch jsch = new JSch();        Session session = jsch.getSession(user, host, port);        session.setPassword(pass);        session.setConfig("StrictHostKeyChecking", "no");        session.connect();        System.out.println("connect OK");        Channel channel = session.openChannel("sftp");        channel.connect();        ChannelSftp channelSftp = (ChannelSftp) channel;        String dir = "LPA";        channelSftp.ls(dir)                .stream()                .filter(lsEntry -> !lsEntry.getFilename().startsWith("."))                .map(lsEntry -> "%s/%s [%d:%d]".formatted(dir, lsEntry.getFilename(), lsEntry.getAttrs().getUId(), lsEntry.getAttrs().getGId()))                .forEach(System.out::println);        channelSftp.exit();    } }mvn -q clean verify connect OK LPA/auth-server [226:207] LPA/euicc-tool [226:207] LPA/device-gateway [226:207] LPA/device-manager [226:207] LPA/javax-smartcardio [226:207] LPA/lpa-server [226:207] LPA/device-manager-interface [226:207] LPA/lpa-interface [226:207] LPA/device-gateway-interface [226:207] LPA/test-device [226:207]

Here's an alternative using NIO and Streams:import java.io.IOException; import java.nio.charset.Charset; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.util.regex.Pattern; import java.util.stream.Collectors; public class AsciiToCsvConverter {    static final Character COLUMN_SEPARATOR_CHAR = 0xA6; // ¦ character    static final String LINE_SEPARATOR = System.lineSeparator(); // OS dependent line separator, change if required    static final String REGEX = "%1$c\\s*([^%1$c]*)\\s*".formatted(COLUMN_SEPARATOR_CHAR);  // %1$c is the column separator character    static final Pattern PATTERN = Pattern.compile(REGEX); // pattern to match interesting lines    static final Charset CHARSET = java.nio.charset.StandardCharsets.ISO_8859_1; // adjust to match file's encoding    public static void main(String[] args) throws IOException {        Path inputPath = Paths.get("D:\\M_SOUTH ECON.asc");        Path outputPath = Paths.get("D:\\M_SOUTH ECON OUT.csv");        String csvData = Files.lines(inputPath, CHARSET) // read lines from file                .map(line -> PATTERN.matcher(line).results() // get matches for values in interesting lines                .map(match -> match.group(1).trim()) // get the value minus any leading/trailing spaces                .collect(Collectors.joining(",")) // to csv line                )                .filter(csv -> !csv.isEmpty()) // remove empty lines                .collect(Collectors.joining(LINE_SEPARATOR));  // to multiline string        Files.writeString(outputPath, csvData, CHARSET); // write to file    } }
Output from the example file would look like this:PointID,Backsight,Intmdt,Foresight,delta H,Distance,Pt Height, Start PtID,,,,,,, B26,,,,,,582.7263, ,,,,,,, B26,5.84220,,,,124.24,, 1,,,3.45202,+2.39019,123.91,585.1165, 1,5.99359,,,,73.47,, M2,,,2.41742,+3.57617,120.08,588.6927, M2,4.43532,,,,44.83,, P1,,3.82759,,+0.60773,77.07,589.3004, M1,,2.43419,,+2.00113,129.85,590.6938, 2,,,4.18279,+0.25254,126.56,588.9452, 2,6.29322,,,,30.13,, M3,,3.73870,,+2.55452,39.23,591.4997, 3,,,1.07662,+5.21660,64.17,594.1618, 3,5.33935,,,,34.29,, P2,,2.82358,,+2.51577,59.53,596.6776, 4,,,2.07683,+3.26252,58.24,597.4243, 4,6.33206,,,,39.11,, 5,,,1.28898,+5.04308,68.21,602.4674, 5,5.60334,,,,32.78,, P3,,2.10250,,+3.50084,63.91,605.9682, 6,,,1.64382,+3.95952,65.29,606.4269, 6,5.83322,,,,39.46,, M6,,2.83305,,+3.00017,44.78,609.4271, 7,,,0.98366,+4.84957,55.94,611.2765, 7,5.14413,,,,34.30,, 8,,,2.47878,+2.66535,41.84,613.9418, 8,6.23389,,,,112.76,, B30,,,3.20561,+3.02828,105.65,616.9701,
CSV file opened in Excel:

The content that you posted looks it has already been processed through something similar to the code you are working with (not only replacing white space with a comma, but also removing ¦ characters).  

Isn't this (below) the type of report that comes from the instrument?  If it is, then I don't think that the code is going to do what you are wanting.

-------------------------------------------------------------------------------------
Leica Geosystems AG --- Digital Level Measurement Report
-------------------------------------------------------------------------------------

-------------------------------------------------------------------------------------
Job name   : 0226ED          
-------------------------------------------------------------------------------------
Operator   : --------        
DNA03      : Instr.Nr.: 343161    
Remarks    : --------         / --------        
Date/Time  : 26.02.2019       /  6:13:39
-------------------------------------------------------------------------------------

-------------------------------------------------------------------------------------
Line Levelling
-------------------------------------------------------------------------------------

Line  : LINE00001        Method: BF        
=====================================================================================
Date  : 26.02.2019       Time  : 06:18:49
Staff1: --------         Staff2: --------        
=====================================================================================
¦     PointID    ¦Backsight ¦  Intmdt  ¦Foresight ¦ delta H  ¦ Distance ¦ Pt Height ¦
-------------------------------------------------------------------------------------
¦Start PtID      ¦          ¦          ¦          ¦          ¦          ¦           ¦
¦B26             ¦          ¦          ¦          ¦          ¦          ¦   582.7263¦
¦                ¦          ¦          ¦          ¦          ¦          ¦           ¦
¦B26             ¦   5.84220¦          ¦          ¦          ¦    124.24¦           ¦
¦1               ¦          ¦          ¦   3.45202¦  +2.39019¦    123.91¦   585.1165¦
¦1               ¦   5.99359¦          ¦          ¦          ¦     73.47¦           ¦
¦M2              ¦          ¦          ¦   2.41742¦  +3.57617¦    120.08¦   588.6927¦
¦M2              ¦   4.43532¦          ¦          ¦          ¦     44.83¦           ¦
¦              P1¦          ¦   3.82759¦          ¦  +0.60773¦     77.07¦   589.3004¦
¦              M1¦          ¦   2.43419¦          ¦  +2.00113¦    129.85¦   590.6938¦
¦2               ¦          ¦          ¦   4.18279¦  +0.25254¦    126.56¦   588.9452¦
¦2               ¦   6.29322¦          ¦          ¦          ¦     30.13¦           ¦
¦              M3¦          ¦   3.73870¦          ¦  +2.55452¦     39.23¦   591.4997¦
¦3               ¦          ¦          ¦   1.07662¦  +5.21660¦     64.17¦   594.1618¦
¦3               ¦   5.33935¦          ¦          ¦          ¦     34.29¦           ¦
¦              P2¦          ¦   2.82358¦          ¦  +2.51577¦     59.53¦   596.6776¦
¦4               ¦          ¦          ¦   2.07683¦  +3.26252¦     58.24¦   597.4243¦
¦4               ¦   6.33206¦          ¦          ¦          ¦     39.11¦           ¦
¦5               ¦          ¦          ¦   1.28898¦  +5.04308¦     68.21¦   602.4674¦
¦5               ¦   5.60334¦          ¦          ¦          ¦     32.78¦           ¦
¦              P3¦          ¦   2.10250¦          ¦  +3.50084¦     63.91¦   605.9682¦
¦6               ¦          ¦          ¦   1.64382¦  +3.95952¦     65.29¦   606.4269¦
¦6               ¦   5.83322¦          ¦          ¦          ¦     39.46¦           ¦
¦              M6¦          ¦   2.83305¦          ¦  +3.00017¦     44.78¦   609.4271¦
¦7               ¦          ¦          ¦   0.98366¦  +4.84957¦     55.94¦   611.2765¦
¦7               ¦   5.14413¦          ¦          ¦          ¦     34.30¦           ¦
¦8               ¦          ¦          ¦   2.47878¦  +2.66535¦     41.84¦   613.9418¦
¦8               ¦   6.23389¦          ¦          ¦          ¦    112.76¦           ¦
¦B30             ¦          ¦          ¦   3.20561¦  +3.02828¦    105.65¦   616.9701¦

Example report downloaded from RPLS.com

What error messages are you seeing?

I tried what I believe is your code after your changes, and it compiled clean.
import java.io.*; import java.util.Scanner; public class AsciiToCsvConverter {    public static void main(String[] args) {        String inputFile = "D:\\M_SOUTH ECON.asc"; // Replace with your ASCII file path        String outputFile = "D:\\M_SOUTH ECON OUT.txt"; // Replace with desired CSV file path        final String CSV_DELIMITER = ","; // Replace with your desired CSV delimiter        try (Scanner scanner = new Scanner(new File(inputFile));             BufferedWriter writer = new BufferedWriter(new FileWriter(outputFile))) {            while (scanner.hasNextLine()) {                String line = scanner.nextLine();                String[] values = line.split("\\s+"); // Split by whitespace                // Join values with the desired delimiter                String csvLine = String.join(CSV_DELIMITER, values);                writer.write(csvLine);                writer.newLine();            }        } catch (IOException e) {            e.printStackTrace();        }    } }
I ran it with D:\M_SOUTH ECON.asc containing this:ST01 Backsight BM01 100.500 2.345 102.845 50.0 ST01 Foresight TP01 102.345 1.500 103.845 50.0
and got output to D:\M_SOUTH ECON OUT.txt containing this:ST01,Backsight,BM01,100.500,2.345,102.845,50.0 ST01,Foresight,TP01,102.345,1.500,103.845,50.0

Jiri Nejedly wrote:Exception in thread "main" com.jcraft.jsch.JSchException: USERAUTH fail (20)

It looks like the (20) in the exception is the last command received (see source below).  According to rfc4253, message #20 is SSH_MSG_KEXINIT; used during the SSH protocol key exchange process (and unexpected in this case).
loop: while (true) { buf = session.read(buf); command = buf.getCommand() & 0xff;  // <<< received command set here if (command == SSH_MSG_USERAUTH_SUCCESS) { return true; } if (command == SSH_MSG_USERAUTH_BANNER) { buf.getInt(); buf.getByte(); buf.getByte(); byte[] _message = buf.getString(); byte[] lang = buf.getString(); String message = Util.byte2str(_message); if (userinfo != null) { try { userinfo.showMessage(message); } catch (RuntimeException ee) {} } continue loop; } if (command == SSH_MSG_USERAUTH_FAILURE) { buf.getInt(); buf.getByte(); buf.getByte(); byte[] foo = buf.getString(); int partial_success = buf.getByte(); methods = Util.byte2str(foo); break; } else { throw new JSchException("USERAUTH fail (" + command + ")");  // <<< where exception was thrown } } return false;com.jcraft.jsch.UserAuthNone       Copyright (c) 2002-2018 ymnk, JCraft,Inc. All rights reserved.

I'm guessing that client and server sides have negotiated to use an authentication scheme other than username/password.

Looking at the source, Jsh is using these schemes by default:
config.put("PreferredAuthentications",
   Util.getSystemProperty("jsch.preferred_authentications",
       "gssapi-with-mic,publickey,keyboard-interactive,password")
);

Try specifying password authentication with:
session.setConfig("PreferredAuthentications", "password");

Also, the second parameter in Session#getSession() is hostname, but your variable named is url.  Make sure this just contains just the hostname part (fqdn or IP address).

The source code for 0.1.72 can be found here: jsch-0.1.72

Please post the stack trace for the exception, and which version you were using.

Since you don't use the index for anything else, you could simplify the code a bit by using an enhanced for loop:for (TestItem testItem : testItems) {    String testcase = testItem.getTestcase();    System.out.println("print String testcase inside loop");    System.out.println(testcase); }