src/main/java/com/github/fracpete/deps4j/MinDeps.java
protected String check() {
    String		error;

    if (!m_JavaHome.exists())
      return "Java home directory does not exist: " + m_JavaHome;
    if (!m_JavaHome.isDirectory())
      return "Java home does not point to a directory: " + m_JavaHome;
    if (System.getProperty("os.name").toLowerCase().contains("windows"))
      m_Jdeps = new File(m_JavaHome.getAbsolutePath() + File.separator + "bin" + File.separator + "jdeps.exe");
    else
      m_Jdeps = new File(m_JavaHome.getAbsolutePath() + File.separator + "bin" + File.separator + "jdeps");
    if (!m_Jdeps.exists())
      return "jdeps binary does not exist: " + m_Jdeps;

    if (!m_ClassesFile.exists())
      return "File with class names does not exist: " + m_ClassesFile;
    if (m_ClassesFile.isDirectory())
      return "File with class names points to directory: " + m_ClassesFile;

    // read classes
    error = readFile(m_ClassesFile, m_Classes);
    if (error != null)
      return error;

    // read resources
    if ((m_AdditionalFile != null) && m_AdditionalFile.exists() && (!m_AdditionalFile.isDirectory())) {
      error = readFile(m_AdditionalFile, m_Resources);
      if (error != null)
	return error;
    }

    return null;
  }
protected String check() {
    String		error;

    if (!m_JavaHome.exists())
      return "Java home directory does not exist: " + m_JavaHome;
    if (!m_JavaHome.isDirectory())
      return "Java home does not point to a directory: " + m_JavaHome;
    if (System.getProperty("os.name").toLowerCase().contains("windows"))
      m_Jdeps = new File(m_JavaHome.getAbsolutePath() + File.separator + "bin" + File.separator + "jdeps.exe");
    else
      m_Jdeps = new File(m_JavaHome.getAbsolutePath() + File.separator + "bin" + File.separator + "jdeps");
    if (!m_Jdeps.exists())
      return "jdeps binary does not exist: " + m_Jdeps;

    if (!m_ClassesFile.exists())
      return "File with class names does not exist: " + m_ClassesFile;
    if (m_ClassesFile.isDirectory())
      return "File with class names points to directory: " + m_ClassesFile;

    // read classes
    error = readFile(m_ClassesFile, m_Classes);
    if (error != null)
      return error;

    // read resources
    if ((m_AdditionalFile != null) && m_AdditionalFile.exists() && (!m_AdditionalFile.isDirectory())) {
      error = readFile(m_AdditionalFile, m_Resources);
      if (error != null)
	return error;
    }

    return null;
  }
Performs some checks.

@return		null if successful, otherwise error message