Beata Szabo-Takacs

Dear Matthew,
Thank you for your response. I could solve the issue based on
the second answer in https://stackoverflow.com/questions/768966/running-2-threads-simultaneously.

I changed my code from FileWriter to void and I set up a Swing Frame in one runnable thread
and I used another thread for file writing and run them simultaneously e.g.

public static void getDataTXT()throws Exception{ Thread thread1 = new Thread(new Runnable() {            public void run() {        final JFrame frame = new JFrame();                      frame.setTitle("Progress");                      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);                       JPanel panel = new JPanel();                        progressbar.setStringPainted(true);                        //progressbar.setIndeterminate(true);                       panel.add(progressbar);                       frame.add(panel);                       frame.setSize(250, 150);                        frame.setVisible(true);        }        }); Thread thread2 = new Thread(new Runnable() {            public void run() {             String txt_file;     fileChooser fc1 = new fileChooser();         txt_file = fc1.fileChooserWindow(4);                try{        FileWriter writer = new FileWriter(txt_file, true);      .......}catch(Exception e){            e.printStackTrace();            }    }        });    thread1.start();    thread2.start(); }

Thank you Tim for your help! I tried your suggestion but unfortunately,
SQL connection blocks the JProgressBar or any GUI. According to
my best knowledge, swingworker should fix it. I do not have experience
in swingworker. Could someone help me how I should use it in the above-
mentioned code?

Thank you for your response!

I would like to use JProgressBar to show the progress of
Java MySql connection. Is there any MySQL query which can use as
JProgressBar setValue()?

I would like to show a running process stage with a pop-up frame. The created a javax.swing.JFrame is:

public class ProcessString extends javax.swing.JFrame {    public void ProcessString(String text) {                        initComponents();                jTextArea1.setText(text);                 this.setLocationByPlatform(true);        this.repaint();    }

The input String text is produced in a for loop like:

 public static int process2;    public static double process; public FileWriter getData()throws Exception{   try{           process = 0.0;           ProcessString b = new ProcessString();            b.setVisible(true); for (int timeIdx = 0; timeIdx < LinesResult; timeIdx ++){            process = (double)timeIdx/LinesResult*100;            process2 = (int) Math.round(process);             String perc = "Completed  " + Integer.toString(process2) + "% of task." ;             b.ProcessString(perc);}

When I use  this.setLocationByPlatform(true) in the Frame it will produce the correct Frame but I will get the error after the first step of the loop:
java.awt.IllegalComponentStateException: The window is showing on screen.
at java.awt.Window.setLocationByPlatform(Window.java:3450)

If I skip the setLocationByPlatform it will produce an empty Frame. Could someone suggest me a way for getting one Frame where the string will change according to the loop?

I have a java program which can download data from MySQL and write them in a chosen file format e.g. TXT. Here is the txt writer:

import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.text.ParseException; import java.text.SimpleDateFormat; import java.io.FileOutputStream; import java.io.FileWriter; import java.util.ArrayList; import java.io.IOException; public class TXT_writer {    private static String okW ="";    private static int countLinesResult = SelectData.countLinesResultS;  // number of sql rows    public static String Table  = SelectData.TableS;  //selected data in string    public static String[] s;    public static String STime =SelectData.STimeSD;  // startime    public static String ETime = SelectData.ETimeSD;  //endtime    public static String listString = SelectData.listStringSD;    private static String header;    private static String data;    private static PreparedStatement statement0;        public static FileWriter getDataTXT()throws Exception{     String txt_file;     fileChooser fc1 = new fileChooser();     // path of the created txt file     txt_file = fc1.fileChooserWindow(4);     FileWriter writer = new FileWriter(txt_file, true);          try{            Connection con = MeteoRead.getConnection();           statement0= con.prepareStatement("SELECT " + listString + " FROM " +Table + " WHERE TIME_ID BETWEEN " +"\"" + STime + "\"" +" AND " + "\"" +ETime + "\"" + " ORDER BY TIME_ID");}                 ResultSet result = statement0.executeQuery();         ResultSet resultV = statement1.executeQuery();            header = "";            s = listString.split(", ");            for(int n=0; n<s.length; n++){             if(n==0){             header = header + "TIME" +"\t";             }             if(n>0 && n<s.length-1){            header = header + s[n] + "\t";            }             if(n==s.length-1){             header = header + s[n] + "\n";             }               }            writer.write(header);                        result.first();            result.previous();            resultV.first();                        while(result.next()){               data = "";                 for(int h=0; h<s.length; h++){                                   if(h < s.length-1){                    data = data + result.getString(s[h]) + "\t";                   }                   if(h==s.length-1){                   data = data + result.getString(s[h]) + "\n";                   }                                  }                 writer.write(data);                             }            writer.close();            okW = "TXT FILE BUILD SUCCESSFULLY";                okWindow o = new okWindow();                o.okWindow(okW);                o.setVisible(true);      con.close();}catch(Exception e){            e.printStackTrace();            }                return writer;}

This writer is called in a JCombobox actionperformed as in an other java file:

private void jComboBox2ActionPerformed(java.awt.event.ActionEvent evt) { if(jComboBox2.getSelectedItem().toString().equals("TXT")){        i=1;           try{             TXT_writer.getDataTXT();             }catch(Exception e){                e.printStackTrace();             }        } dispose() }

I would like to show the progress of the writer with JprogrssBar, but I do not know how should
I measure the writer progress (i.e. the integer value for set the JprogressBar value). Could someone suggest me a solution?

Finally, I could solve the matter. I checked the code
on Linux OS where the java path was jdk\jre. I changed the path of
the java to jdk\bin by editing the .bash_profile. The code works now.

I used cmd and I applied the command line as you posted. It works correctly. But I do not understand why does not work correctly if I just click to the .jar file?

Dear Norm,
Thank you so much for your suggestion. It works correctly. What do you think I should set the path of the environment variables as C:\Program Files\Java\jdk1.8_151\bin\java.exe?

Dear Tim,
I have tried it but I got the error that the currency.data is missing. I have the same problem as in: https://stackoverflow.com/questions/49711640/javacompiler-always-null-with-jdk-versions-1-8-0
I need the InMemoryJavaCompiler because I wrote a java Class with StringBuilder and I have to compile it. Here are the details of my purpose: https://coderanch.com/t/725893/java/convert-strings-executable-Java-code#3378151
I do not understand why does not work the .jar file which was developed and built in NetBeans 8.1 IDE? If I understand well NetBeans has compact profiles which contain the required javax.tools but I do not understand why the javax.tools "is missing" or the created .jar file does not find after the packing and building.

I use NetBeans 8.1 for developing a Java project. I use InMemoryJavaCompiler in two classes. When I run the project under NetBeans it works correctly. I created a .jar file from the project with properties -- > packing and properties -- > Clean and Build. When I try to run the .jar file the program does not work. It generates a NullPointerException regarding InMemoryJavaCompiler:
java.lang.NullPointerException        at org.mdkt.compiler.InMemoryJavaCompiler.compileAll(InMemoryJavaCompiler.java:80)
According to https://stackoverflow.com/questions/2543439/null-pointer-exception-while-using-java-compiler-api most probably the ToolProvider.getSystemJavaCompiler() returns null. I checked the java.home in NetBeans with System.out.println(System.getProperty("java.home")) which is:
C:\Program Files\Java\jdk1.8.0_151\jre
I tried to add and move up the tools.jar from Java\jdk1.8.0_151\lib in NetBeans project -- > properties -- > Libraries: Compiles and built again the program but it doses not help. On my computer, the java path is C:\Program Files\Java\jdk1.8.0_151\bin.
Could someone suggest me a solution to fix the nullpointerexception error?

Here is the ComPiler.java class where I used InMemoryJavaCompiler:

package meteoread; import javax.activation.DataSource; import org.mdkt.compiler.InMemoryJavaCompiler; import ucar.nc2.Variable; import ucar.nc2.NetcdfFileWriter; import ucar.nc2.*; import ucar.ma2.*; public class ComPiler {        public static String Var = SelectData.VariablesSD;    public static String DA = SelectData.DataASD;    public static String DD = SelectData.DataDSD;    public static String DNC = SelectData.DataNCSD;    public static String TableNC = SelectData.TableS;    public static String STime =SelectData.STimeSD;    public static String ETime = SelectData.ETimeSD;    public static int countLinesResult = SelectData.countLinesResultS;    public static String listString = SelectData.listStringSD;    public static String SDim = SelectData.DIM;    public static String flag = SelectData.sl;        public static void CodeFromString()throws Exception{        System.out.println("CodeFromString");           StringBuilder sourceCode = new StringBuilder();                sourceCode.append("package meteoread;\n");                sourceCode.append("import ucar.nc2.*;\n" +                 "import ucar.ma2.*; \n" +"import java.sql.Connection;\n" +                 "import java.sql.PreparedStatement;\n" +                 "import java.sql.ResultSet;\n" +                 "import java.sql.ResultSetMetaData;\n" +                 "import java.text.ParseException;\n" +                  "import java.text.SimpleDateFormat;\n" +                 "import java.util.ArrayList;\n" +                  "import java.util.Calendar;\n" +                  "import java.util.Date;\n" +                  "import java.util.GregorianCalendar;\n" +                  "import java.util.Iterator;\n" +                  "import java.util.List;\n"                                                                                      + "import java.io.IOException;\n");                sourceCode.append("public class NC_writer implements DataNcSource {\n");                sourceCode.append("private static String okW =\"\";\n" +                                                              " public static ArrayList<Double> ValueD = new ArrayList<Double>();\n"                         +                        "public static String Var = SelectData.VariablesSD;\n" +                        "public static String DA = SelectData.DataASD;\n" +                        "public static String DD = SelectData.DataDSD;\n" +                        "public static String DNC = SelectData.DataNCSD;\n" +                        "public static String TableNC = SelectData.TableS;\n" +                        "public static String STime =SelectData.STimeSD;\n" +                        "public static String ETime = SelectData.ETimeSD;\n" +                        "public static int countLinesResult = SelectData.countLinesResultS;\n" +                        "public static String listString = SelectData.listStringSD;\n"                        + "public static String SDim = SelectData.DIM;\n"                        +"private static SimpleDateFormat formatter;\n"                        + "public static String Filter = SelectData.CFlag;\n"                        + "private static PreparedStatement statement0;\n"                        + "public static String flag = SelectData.sl;\n"                        + "public static int FT = SelectData.FT;\n"                        + "private static ResultSet result;\n"                                                                                                                    );                              sourceCode.append("public NetcdfFileWriter getDataNc()throws Exception{\n "                        + "String location;\n"                        + "fileChooser fc1 = new fileChooser();\n" +                          "location = fc1.fileChooserWindow(1);\n"                        +                      "NetcdfFileWriter ncfile = NetcdfFileWriter.createNew(NetcdfFileWriter.Version.netcdf4, location, null);\n" +                        SDim +                         "\n" +                        "try{\n" +                                             "Connection con = MeteoRead.getConnection();\n"                                                                   + "if(FT == 0){"                          + " statement0= con.prepareStatement(\"SELECT \" + listString + \" FROM \" +TableNC + \" WHERE TIME_ID BETWEEN \" +\"\\\"\" + STime + \"\\\"\" +\" AND \" + \"\\\"\" +ETime + \"\\\"\" + \" ORDER BY TIME_ID\");} \n"                    + "else if(FT == 1){"                       + "statement0= con.prepareStatement(\"SELECT \" + listString + \" FROM \" +TableNC + \" WHERE TIME_ID BETWEEN \" +\"\\\"\" + STime + \"\\\"\" +\" AND \" + \"\\\"\" +ETime + \"\\\"\" + \" AND \" + flag + \" = \" +\"\\\"\" + Filter.trim() +\"\\\"\" + \" ORDER BY TIME_ID\");"                    + "}\n"                     + "else if(FT == 2){"                        + "statement0= con.prepareStatement(\"SELECT \" + listString + \" FROM \" +TableNC + \" WHERE TIME_ID BETWEEN \" +\"\\\"\" + STime + \"\\\"\" +\" AND \" + \"\\\"\" +ETime + \"\\\"\" + \" AND \" + flag + \" = \" + Integer.parseInt(Filter.trim()) + \" ORDER BY TIME_ID\");"                     + "}\n"                     + "else if(FT == 3){"                        + "statement0= con.prepareStatement(\"SELECT \" + listString + \" FROM \" +TableNC + \" WHERE TIME_ID BETWEEN \" +\"\\\"\" + STime + \"\\\"\" +\" AND \" + \"\\\"\" +ETime + \"\\\"\" + \" AND \" + flag + \" = \" + Double.parseDouble(Filter.trim()) + \" ORDER BY TIME_ID\");"                     + "}\n"                                            +                                                               " result = statement0.executeQuery();\n" +                     " ResultSetMetaData rsmd = result.getMetaData();\n" +                     " result.first();\n" +                     " result.previous();\n"                                +Var +" ncfile.create();\n"                        + DA                        + "    while(result.next()){\n"                      //  + "System.out.println(\"Time_ID: \" + result.getString(\"TIME_ID\"));" +                       +  "Date date2 = dateConv1(result.getString(\"TIME_ID\"));\n" +                          "double dateU = ToMATLABDate(date2);\n" +                           "ValueD.add(dateU);\n"                     //   + "System.out.println(\"ValueD: \" + ValueD.get(0));"                          + "}\n"                       // + "System.out.println(\"Value(ManualDescriptiveFlag): \"+ Value(\"ManualDescriptiveFlag\"));\n"                      //  + "System.out.println(\"countLineResult: \" + countLinesResult);"+                       + " for (int timeIdx = 0; timeIdx < countLinesResult; timeIdx ++){\n" +                         DD+"}\n"                                                + DNC +"\n"                                                                      + "ncfile.close();\n"                        + "con.close();\n"                       + " okW = \"NC FILE BUILD SUCCESSFULLY\";\n" +                        " okWindow o = new okWindow();\n" +                        " o.okWindow(okW);\n" +                        " o.setVisible(true);\n" +                          " } catch(Exception e){\n" +                         "  e.printStackTrace();\n" +                         " okW = e.toString();\n" +                        " okWindow o = new okWindow();\n" +                        " o.okWindow(okW);\n" +                        " o.setVisible(true);}\n" +                        "  return ncfile;} "                        + "\n");                                sourceCode.append("public Date dateConv1(String s){\n" +                  "if(s.length()==19 && s.contains(\"-\")){" +                             " formatter = new SimpleDateFormat(\"yyyy-MM-dd HH:mm:ss\");}\n"                        + "if(s.length()==19 && s.contains(\".\")){"                        + "formatter = new SimpleDateFormat(\"yyyy.MM.dd HH:mm:ss\");}\n" +                  "if(s.length() == 23 && s.contains(\"-\")){"                        + "formatter = new SimpleDateFormat(\"yyyy-MM-dd HH:mm:ss.SSS\");}\n"                        + "if(s.length() == 23 && s.contains(\".\")){"                        + "formatter = new SimpleDateFormat(\"yyyy.MM.dd HH:mm:ss.SSS\");}\n"                        + "if(s.length() == 16 && s.contains(\"-\")){"                        + "formatter = new SimpleDateFormat(\"yyyy-M-d H:mm:ss\");}\n"+                        " String dateInString = s;\n" +                  " Date date = new Date();\n" +                  " try {\n" +                  " date = (Date)formatter.parse(dateInString);\n" +                  " } catch (ParseException e) {\n" +                  " e.printStackTrace();\n" +                  " }\n" +                  " return date;\n" +                  " }\n");                sourceCode.append("public double ToMATLABDate(Date date) {\n" +                " // Converts a java.util.Date into a MATLAB Serial Date Number taking into account timezones and DST.\n" +                " Calendar cal = new GregorianCalendar();\n" +                " cal.setTime(date);\n" +                " double SerialDateNumber = (date.getTime() + cal.get(Calendar.ZONE_OFFSET) + cal.get(Calendar.DST_OFFSET)) / 1000.0 / 3600.0 / 24.0 ;\n" +                " return SerialDateNumber;\n" +                " }");                sourceCode.append("public String getStringDD(int i){"                        + "String S;\n"                        + "String [] str = DD.split(\"\\n\");\n"                        + "S = str[i];\n"                        + "return S;}\n");                sourceCode.append("public String getStringDNC(int i){"                        + "String S;\n"                        + "String [] str = DNC.split(\"\\n\");\n"                        + "S = str[i];\n"                        + "return S;}\n");                              sourceCode.append("public ArrayList<String> Value(String colName)throws Exception{\n"                      //  + "System.out.println(\" OK \");"                        + "ArrayList<String> array = new ArrayList<String>();\n"+                        "try{\n"                                                + "result.first();\n" +                       "result.previous();\n" +                          "while(result.next()){\n" +                          "array.add(result.getString(colName));\n" +                                   "}\n"                                           +   "}catch(Exception e){\n" +                        "e.printStackTrace();\n" +                         "}\n" +                         "return array;}\n");                sourceCode.append("public ArrayList<Double> backscatter(String s){\n"                        + "int digit1 = 0;\n"                        + "double digit =0.0;\n"                        + "String ss;\n"                        + "double digit2;\n"                        + "ArrayList<Double> bcdigit = new ArrayList<Double>();\n"                                                +    "for(int i=0; i < s.length()-5; i=i+5){\n"                        +    "ss = s.substring(i,i+5);\n"                        +    "digit1 = Integer.parseInt(ss,16);\n"                        +    "digit = digit1 * 1.0;\n"                        +      "if(digit > Math.pow(2.0, 19.0)){\n"                        +      "digit = -(Math.pow(2.0, 20.0) - digit);\n"                        +      "}\n"                        +   "digit2 = digit* 0.00001;\n"                        +   "bcdigit.add(digit2);}\n"                                              + "return bcdigit;}\n");                sourceCode.append("public List<List<Double>> hx2D(String colName)throws Exception{\n"                        + "List<List<Double>> hxD = new ArrayList<List<Double>>();\n"                        + "try{\n"                                      + "result.first();\n"                        + "result.previous();\n"                        + "while(result.next()){\n"                        +  "hxD.add(backscatter(result.getString(colName)));\n"                        + "}"                                      + "}catch(Exception e){\n"                        + "e.printStackTrace();\n}"                        + "return hxD;}\n");                sourceCode.append(""                        + "}");            //    System.out.println(sourceCode);                 Class<?> Netcdf_writer = InMemoryJavaCompiler.compile("meteoread.NC_writer", sourceCode.toString());                 DataNcSource instance = (DataNcSource) Netcdf_writer.newInstance();                instance.getDataNc();                      }     }

and here is the part of the code where I called the ComPiler Class:
 try{               ComPiler.CodeFromString();              }catch(Exception e){            e.printStackTrace();        }                    }
I receive the following error:
java.lang.NullPointerException
       at org.mdkt.compiler.InMemoryJavaCompiler.compile(InMemoryJavaCompiler.java:19)
       at meteoread.ComPiler.CodeFromString(ComPiler.java:261)
....

The JDK 1.8 is installed on my PC.

I wrote a Java project in NetBeans IDE. This project contains two abstract Java Classes which are compiled with InMemoryJavaCompiler.
When I run the code in the IDE it works. I produced a .jar file from this project with build packing and clear and build.
When I run the .jar file I receive a NullPointerException error when I use the abstract classes.
Could someone suggest some solution?
Thank you for your help in advance!

Dear All,
I would like to use an AWT label to show the error messages in a JFrame.
I tried to set the label size according to the text size. Here is my code:

public class okW extends javax.swing.JFrame { public void okW(String s) {         initComponents();       label1.setSize(s.length(), 1);         label1.setText(s);               this.setLocationRelativeTo(null);   } }

When I get a long error message e.g.:
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
Communications link failure

only one part of this text will be shown. Could someone suggest me a solution to fix this issue?
Thank you for your help in advance!

Thank you very much Tim for your suggestion! I accepted. I could solve the issue with the following code:

import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.text.ParseException; import java.text.SimpleDateFormat; import java.io.FileOutputStream; import java.io.FileWriter; import java.io.IOException; import java.io.InputStream; import java.sql.Blob; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.pdmodel.PDPage; import org.apache.pdfbox.pdmodel.common.PDRectangle; import org.apache.pdfbox.pdmodel.PDPageContentStream; import org.apache.pdfbox.pdmodel.font.PDFont; import org.apache.pdfbox.pdmodel.font.PDType1Font; import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;         public class ImageWriter { private static FileOutputStream fos;   private static byte[] buf;   private static int len;   private static InputStream buf2;     public static FileOutputStream getImages()throws Exception{      String query = "SELECT Image FROM IMAGES" ;       fileChooser fc1 = new fileChooser();         String fileName = fc1.fileChooserWindow(5);       PDDocument document = new PDDocument();       PDPage page = new PDPage(PDRectangle.A4);       PDPageContentStream cos = new PDPageContentStream(document, page);                   try{            Connection con = MeteoRead.getConnection();            PreparedStatement pst = con.prepareStatement(query);            ResultSet result = pst.executeQuery();                         if (result.next()) {                                  fos = new FileOutputStream(fileName);                    Blob blob = result.getBlob("Image");                    len = (int) blob.length();                    if(fileName.contains("pdf")){                                                try {                            buf = blob.getBytes(1, len);                            PDImageXObject imageObject = PDImageXObject.createFromByteArray(document, buf, null);                            float scale = 0.4f; // alter this value to set the image size                                                        cos.drawImage(imageObject, 100, 400, imageObject.getWidth()*scale, imageObject.getHeight()*scale);                                                                              } catch (IOException ioex) {                                System.out.println("No image for you");                            }                                                                          }else{                    buf = blob.getBytes(1, len);                    fos.write(buf, 0, len);                           }                 }                   con.close();                   fos.close();                      cos.close();                       document.addPage(page);        // Save the results and ensure that the document is properly closed:                           document.save(fileName);                           document.close(); return fos; }     }