diff --git a/src/main/java/ru/ulstu/extractor/heuristic/api/StructuralUnitIdentifier.java b/src/main/java/ru/ulstu/extractor/heuristic/api/StructuralUnitIdentifier.java
index 3217e51..f086fb8 100644
--- a/src/main/java/ru/ulstu/extractor/heuristic/api/StructuralUnitIdentifier.java
+++ b/src/main/java/ru/ulstu/extractor/heuristic/api/StructuralUnitIdentifier.java
@@ -9,6 +9,7 @@ import ru.ulstu.extractor.heuristic.component.BuildTool;
 import ru.ulstu.extractor.heuristic.component.ProgrammingLanguage;
 import ru.ulstu.extractor.heuristic.model.StructuralUnit;
 import ru.ulstu.extractor.heuristic.service.DetectorService;
+import ru.ulstu.extractor.util.StringUtils;
 
 import java.io.File;
 import java.io.FileNotFoundException;
@@ -43,16 +44,19 @@ public abstract class StructuralUnitIdentifier {
 
     protected abstract boolean isBusinessLogicClass(File file);
 
-    protected Optional<ProgrammingLanguage> getMainProgrammingLanguage(List<File> projectFiles) {
+    protected Optional<ProgrammingLanguage> getMainProgrammingLanguage(String projectPath, List<File> projectFiles, List<File> rootProjectFiles) {
+        String subDirectory = getSourceDirectory(rootProjectFiles);
         Map<String, Integer> projectFileLanguageFrequency = new HashMap<>();
-        projectFiles.forEach(projectFile -> {
-            try {
-                String detectedLanguage = getDetectorService().getDetectedLanguage(new String(Files.readAllBytes(projectFile.toPath())));
-                projectFileLanguageFrequency.put(detectedLanguage, projectFileLanguageFrequency.getOrDefault(detectedLanguage, 0) + 1);
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
-        });
+        projectFiles.stream()
+                .filter(file -> StringUtils.fileInSubdirectory(file.getPath(), projectPath, subDirectory))
+                .forEach(projectFile -> {
+                    try {
+                        String detectedLanguage = getDetectorService().getDetectedLanguage(new String(Files.readAllBytes(projectFile.toPath())));
+                        projectFileLanguageFrequency.put(detectedLanguage, projectFileLanguageFrequency.getOrDefault(detectedLanguage, 0) + 1);
+                    } catch (IOException e) {
+                        e.printStackTrace();
+                    }
+                });
 
         Optional<Map.Entry<String, Integer>> mostFrequentLanguageEntry = projectFileLanguageFrequency
                 .entrySet()
@@ -68,5 +72,5 @@ public abstract class StructuralUnitIdentifier {
                 : Optional.empty();
     }
 
-    public abstract boolean canAppliedToProject(List<File> projectFiles);
+    public abstract boolean canAppliedToProject(String projectPath, List<File> projectFiles, List<File> rootProjectFiles);
 }
diff --git a/src/main/java/ru/ulstu/extractor/heuristic/service/JavaIdentifier.java b/src/main/java/ru/ulstu/extractor/heuristic/service/JavaIdentifier.java
index 0575698..cf7ff7c 100644
--- a/src/main/java/ru/ulstu/extractor/heuristic/service/JavaIdentifier.java
+++ b/src/main/java/ru/ulstu/extractor/heuristic/service/JavaIdentifier.java
@@ -11,9 +11,7 @@ import com.github.javaparser.ast.CompilationUnit;
 import org.springframework.stereotype.Service;
 import ru.ulstu.extractor.heuristic.api.StructuralUnitIdentifier;
 import ru.ulstu.extractor.heuristic.component.BuildTool;
-import ru.ulstu.extractor.heuristic.component.GradleBuildTool;
 import ru.ulstu.extractor.heuristic.component.JavaProgrammingLanguage;
-import ru.ulstu.extractor.heuristic.component.MavenBuildTool;
 import ru.ulstu.extractor.heuristic.component.ProgrammingLanguage;
 import ru.ulstu.extractor.heuristic.model.EntityUnit;
 import ru.ulstu.extractor.heuristic.model.StructuralUnit;
@@ -37,9 +35,9 @@ public class JavaIdentifier extends StructuralUnitIdentifier {
     }
 
     @Override
-    public boolean canAppliedToProject(List<File> projectFiles) {
+    public boolean canAppliedToProject(String projectPath, List<File> projectFiles, List<File> rootProjectFiles) {
         return /*getBuildTool() instanceof GradleBuildTool
-                &&*/ getMainProgrammingLanguage(projectFiles).orElse(null) instanceof JavaProgrammingLanguage;
+                &&*/ getMainProgrammingLanguage(projectPath, projectFiles, rootProjectFiles).orElse(null) instanceof JavaProgrammingLanguage;
     }
 
     @Override
@@ -62,18 +60,8 @@ public class JavaIdentifier extends StructuralUnitIdentifier {
     }
 
     @Override
-    public Optional getBuildTool(List<File> rootDirectoryFiles) {
-        //Todo: refactoring is highly recommended
-        Optional<GradleBuildTool> maybeGradleBuildTool = rootDirectoryFiles.stream()
-                .filter(file -> file.getName().equals("build.gradle"))
-                .findAny().map(file -> new GradleBuildTool());
-
-        if (maybeGradleBuildTool.isPresent()) {
-            return maybeGradleBuildTool;
-        }
-        return rootDirectoryFiles.stream()
-                .filter(file -> file.getName().equals("pom.xml"))
-                .findAny().map(file -> new MavenBuildTool());
+    public Optional<BuildTool> getBuildTool(List<File> rootDirectoryFiles) {
+        return buildToolService.getProjectBuildTool(rootDirectoryFiles);
     }
 
     @Override
diff --git a/src/main/java/ru/ulstu/extractor/heuristic/service/StructuralUnitService.java b/src/main/java/ru/ulstu/extractor/heuristic/service/StructuralUnitService.java
index 3772e5d..848ab20 100644
--- a/src/main/java/ru/ulstu/extractor/heuristic/service/StructuralUnitService.java
+++ b/src/main/java/ru/ulstu/extractor/heuristic/service/StructuralUnitService.java
@@ -33,7 +33,7 @@ public class StructuralUnitService {
         List<File> projectFiles = directoryService.getFilesRecursively(rootPath);
         List<File> rootProjectFiles = directoryService.getDirectoryFiles(rootPath.toPath());
         StructuralUnitIdentifier selectedIdentifier = structuralUnitIdentifiers.stream()
-                .filter(structuralUnitIdentifier -> structuralUnitIdentifier.canAppliedToProject(projectFiles))
+                .filter(structuralUnitIdentifier -> structuralUnitIdentifier.canAppliedToProject(rootPath.getPath(), projectFiles, rootProjectFiles))
                 .findAny()
                 .orElseThrow(() -> new RuntimeException("Identifier not found"));
         return selectedIdentifier.getEntityClasses(rootPath.getPath(), projectFiles, rootProjectFiles);