public void buildTypeGraph() {
    Map<String, JarFile> openJarFiles = new HashMap<String, JarFile>();
    Map<String, File> openClassFiles = new HashMap<String, File>();
    // use global cache to load resource in/out of the same jar as the classes
    Set<String> resourceCacheSet = new HashSet<>();
    try {
      for (String path : pathsToScan) {
        File f = null;
        try {
          f = new File(path);
          if (!f.exists()
              || f.isDirectory()
              || (!f.getName().endsWith("jar") && !f.getName().endsWith("class"))) {
            continue;
          }
          if (GENERATED_CLASSES_JAR.equals(f.getName())) {
            continue;
          }
          if (f.getName().endsWith("class")) {
            typeGraph.addNode(f);
            openClassFiles.put(path, f);
          } else {
            JarFile jar = new JarFile(path);
            openJarFiles.put(path, jar);
            java.util.Enumeration<JarEntry> entriesEnum = jar.entries();
            while (entriesEnum.hasMoreElements()) {
              final java.util.jar.JarEntry jarEntry = entriesEnum.nextElement();
              String entryName = jarEntry.getName();
              if (jarEntry.isDirectory()) {
                continue;
              }
              if (entryName.endsWith("-javadoc.xml")) {
                try {
                  processJavadocXml(jar.getInputStream(jarEntry));
                  // break;
                } catch (Exception ex) {
                  LOG.warn("Cannot process javadoc {} : ", entryName, ex);
                }
              } else if (entryName.endsWith(".class")) {
                TypeGraph.TypeGraphVertex newNode = typeGraph.addNode(jarEntry, jar);
                // check if any visited resources belong to this type
                for (Iterator<String> iter = resourceCacheSet.iterator(); iter.hasNext(); ) {
                  String entry = iter.next();
                  if (entry.startsWith(entryName.substring(0, entryName.length() - 6))) {
                    newNode.setHasResource(true);
                    iter.remove();
                  }
                }
              } else {
                String className = entryName;
                boolean foundClass = false;
                // check if this resource belongs to any visited type
                while (className.contains("/")) {
                  className = className.substring(0, className.lastIndexOf('/'));
                  TypeGraph.TypeGraphVertex tgv = typeGraph.getNode(className.replace('/', '.'));
                  if (tgv != null) {
                    tgv.setHasResource(true);
                    foundClass = true;
                    break;
                  }
                }
                if (!foundClass) {
                  resourceCacheSet.add(entryName);
                }
              }
            }
          }
        } catch (IOException ex) {
          LOG.warn("Cannot process file {}", f, ex);
        }
      }

      typeGraph.trim();

      typeGraph.updatePortTypeInfoInTypeGraph(openJarFiles, openClassFiles);
    } finally {
      for (Entry<String, JarFile> entry : openJarFiles.entrySet()) {
        try {
          entry.getValue().close();
        } catch (IOException e) {
          DTThrowable.wrapIfChecked(e);
        }
      }
    }
  }