remove JLR library using

src/main/java/ru/ulstu/paper/controller/PaperController.java

@@ -118,7 +118,7 @@ public class PaperController {
     }
 
     @PostMapping("/generatePdf")
-    public ResponseEntity<byte[]> getPdfFile(PaperDto paper) throws IOException {
+    public ResponseEntity<byte[]> getPdfFile(PaperDto paper) throws IOException, InterruptedException {
         HttpHeaders headers = new HttpHeaders();
         headers.add("Content-Disposition", "attachment; filename='" +
                 URLEncoder.encode(paper.getTitle() + ".pdf", UTF_8.toString()) + "'");

src/main/java/ru/ulstu/paper/service/LatexService.java

@@ -1,33 +1,74 @@
 package ru.ulstu.paper.service;
 
-import de.nixosoft.jlr.JLRGenerator;
 import org.springframework.stereotype.Service;
 import ru.ulstu.file.service.FileService;
 import ru.ulstu.paper.model.PaperDto;
 
+import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStreamReader;
 import java.nio.file.Files;
 
 @Service
 public class LatexService {
+    private String errorMessage;
+    private File pdfFile;
     private FileService fileService;
+    private final String pdfLatexError = "Errors occurred while executing pdfLaTeX.";
+    private final String bibtexError = "Errors occurred while executing bibtex.";
 
     public LatexService(FileService fileService) {
         this.fileService = fileService;
     }
 
-    public byte[] generatePdfFromLatexFile(PaperDto paper) throws IOException {
+    public byte[] generatePdfFromLatexFile(PaperDto paper) throws IOException, InterruptedException {
         fileService.createLatexAttachs(paper);
         File tex = fileService.createLatexFile(paper);
 
-        File output = new File(tex.getParentFile().getAbsolutePath() + File.separator);
-        JLRGenerator pdfGen = new JLRGenerator();
+        if (!generate(paper.getTitle(), tex.getParentFile())) {
+            throw new IOException(errorMessage);
+        }
+
+        return Files.readAllBytes(pdfFile.toPath());
+    }
+
+    private int startProcess(String[] args, File dir, String message) throws IOException, InterruptedException {
+        ProcessBuilder processBuilder = new ProcessBuilder(args);
+        processBuilder.redirectErrorStream(true);
+        processBuilder.directory(dir);
+
+        Process process = processBuilder.start();
+        InputStreamReader inputStreamReader = new InputStreamReader(process.getInputStream());
+        BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
+
+        try {
+            while ((bufferedReader.readLine()) != null) ;
+        } finally {
+            bufferedReader.close();
+        }
 
-        if (!pdfGen.generate(tex, output, tex.getParentFile())) {
-            throw new IOException(pdfGen.getErrorMessage());
+        int exitCode = process.waitFor();
+        if (exitCode != 0) {
+            errorMessage = message + " Exit value of the process: " + exitCode;
         }
+        return exitCode;
+    }
+
+    private boolean generate(String filename, File dir) throws IOException, InterruptedException {
+        if (startProcess(new String[]{"pdflatex", filename}, dir, pdfLatexError) != 0) return false;
+        startProcess(new String[]{"bibtex", filename}, dir, bibtexError);
+        if (startProcess(new String[]{"pdflatex", filename}, dir, pdfLatexError) != 0) return false;
+        return checkPdf(filename, dir);
+    }
+
+    private boolean checkPdf(String filename, File dir) {
+        pdfFile = new File(dir.getAbsolutePath() + File.separator + filename + ".pdf");
 
-        return Files.readAllBytes(pdfGen.getPDF().toPath());
+        if (pdfFile.isFile()) return true;
+        else {
+            errorMessage = "The pdf file could not be created.";
+            return false;
+        }
     }
 }