diff --git a/src/CurlHelper.java b/src/main/java/sjpapi/api/CurlHelper.java
similarity index 78%
rename from src/CurlHelper.java
rename to src/main/java/sjpapi/api/CurlHelper.java
index 8c97b96..7278040 100644
--- a/src/CurlHelper.java
+++ b/src/main/java/sjpapi/api/CurlHelper.java
@@ -4,9 +4,11 @@
 
 public class CurlHelper {
 
-    private final static CurlReader reader = new CurlReader();
-    private final static CurlValidator validator = new CurlValidator();
+    private static final CurlReader reader = new CurlReader();
+    private static final CurlValidator validator = new CurlValidator();
 
+    private CurlHelper() {
+    }
 
     public static String getOutputFromCurl(String word) throws IOException {
 
@@ -25,10 +27,4 @@ public static String getOutputFromCurl(String word) throws IOException {
     private static String readCurlFromSJP(String word) throws IOException {
         return reader.getCurlOutput("https://sjp.pl/"+word);
     }
-
-
-
-
-
-
 }
diff --git a/src/CurlReader.java b/src/main/java/sjpapi/api/CurlReader.java
similarity index 70%
rename from src/CurlReader.java
rename to src/main/java/sjpapi/api/CurlReader.java
index 608d9ec..ac6ed93 100644
--- a/src/CurlReader.java
+++ b/src/main/java/sjpapi/api/CurlReader.java
@@ -6,27 +6,25 @@
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.SEVERE;
 
 public class CurlReader {
 
-    private String readed = "";
+    private String readResult = "";
+    private static final Logger logger = Logger.getLogger(CurlReader.class.getName());
 
     public String getCurlOutput(final String https) {
 
-
-        Thread thread = new Thread(new Runnable() {
-            @Override
-            public void run() {
-                try {
-                    try {
-                        readed = CurlReader.this.read(https);
-                    } catch (MalformedURLException e) {
-                        e.printStackTrace();
-                    }
-
-                } catch (Exception e) {
-                    e.printStackTrace();
-                }
+        Thread thread = new Thread(() -> {
+            try {
+                readResult = read(https);
+            } catch (MalformedURLException e) {
+                logger.log(SEVERE, "MalformedURLException");
+                e.printStackTrace();
+            } catch (IOException e) {
+                e.printStackTrace();
             }
         });
         thread.start();
@@ -34,8 +32,9 @@ public void run() {
             thread.join();
         } catch (InterruptedException e) {
             e.printStackTrace();
+            Thread.currentThread().interrupt();
         }
-        return readed;
+        return readResult;
     }
 
 
@@ -57,12 +56,9 @@ private String read(String https) throws IOException {
 
             BufferedReader br;
             String response = curlOutput.toString();
-            if ("404".equals(response))
-            {
+            if ("404".equals(response)) {
                 br = new BufferedReader(new InputStreamReader(urlConnection.getErrorStream()));
-            }
-            else
-            {
+            } else {
                 br = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
             }
 
@@ -72,13 +68,10 @@ private String read(String https) throws IOException {
             }
             br.close();
             urlConnection.disconnect();
-        }
-        catch(Exception e) {
+        } catch (Exception e) {
             curlOutput = new StringBuilder();
         }
 
         return curlOutput.toString();
     }
-
-
 }
diff --git a/src/CurlValidator.java b/src/main/java/sjpapi/api/CurlValidator.java
similarity index 74%
rename from src/CurlValidator.java
rename to src/main/java/sjpapi/api/CurlValidator.java
index 89fbb49..e3a10dc 100644
--- a/src/CurlValidator.java
+++ b/src/main/java/sjpapi/api/CurlValidator.java
@@ -13,9 +13,6 @@ private Boolean isResponseOK( String curlOutput ) {
     }
 
     private Boolean isBodySection( String curlOutput ) {
-        if (curlOutput.contains("<body>") && curlOutput.contains("</body>")){
-            return true;
-        }
-        return false;
+        return curlOutput.contains("<body>") && curlOutput.contains("</body>");
     }
 }
diff --git a/src/SjpAPI.java b/src/main/java/sjpapi/api/SjpAPI.java
similarity index 93%
rename from src/SjpAPI.java
rename to src/main/java/sjpapi/api/SjpAPI.java
index d88f0e7..28e9339 100644
--- a/src/SjpAPI.java
+++ b/src/main/java/sjpapi/api/SjpAPI.java
@@ -6,6 +6,9 @@
 
 public class SjpAPI {
 
+    private SjpAPI() {
+    }
+
     public static String getWord(String word) throws IOException, JSONException {
         String json;
         String wordWithoutSpecialChar;
diff --git a/src/SjpHelper.java b/src/main/java/sjpapi/api/SjpHelper.java
similarity index 94%
rename from src/SjpHelper.java
rename to src/main/java/sjpapi/api/SjpHelper.java
index 363e615..3420a53 100644
--- a/src/SjpHelper.java
+++ b/src/main/java/sjpapi/api/SjpHelper.java
@@ -9,6 +9,9 @@ public class SjpHelper {
     private static final SjpValidator validator = new SjpValidator();
     private static final SjpWrapper wrapper = new SjpWrapper();
 
+    private SjpHelper() {
+    }
+
     public static String translateFromCurlToJSON(String curl ) throws JSONException, UnsupportedEncodingException {
 
         String json = "EMPTY";
diff --git a/src/SjpValidator.java b/src/main/java/sjpapi/api/SjpValidator.java
similarity index 100%
rename from src/SjpValidator.java
rename to src/main/java/sjpapi/api/SjpValidator.java
diff --git a/src/SjpWrapper.java b/src/main/java/sjpapi/api/SjpWrapper.java
similarity index 93%
rename from src/SjpWrapper.java
rename to src/main/java/sjpapi/api/SjpWrapper.java
index a6656b4..62aae70 100644
--- a/src/SjpWrapper.java
+++ b/src/main/java/sjpapi/api/SjpWrapper.java
@@ -20,7 +20,7 @@ public String getWrapped (String curlOutput) throws JSONException, UnsupportedEn
     private List<List<String>> regexForInfo (String curlOutput) {
 
         List<List<String>> wrappedCurl = new ArrayList<>();
-        if (isInDictionary(curlOutput)) {
+        if (Boolean.TRUE.equals(isInDictionary(curlOutput))) {
 
             final String regex = "<h1[^>]*>(.+?)<\\/h1>.<p[^>]*>(.+?)<.+?(?=.*)href=\"\\/(.+?)\".+?znaczenie.+?<p[^>]*>(.+?)<\\/p>";
             final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
@@ -59,7 +59,7 @@ private String translateArrayToJSON(List<List<String>> wordsFromCurlOutput ) thr
             jsonObject.put("name",wordsFromCurlOutput.get(0).get(0));
             jsonObject.put("count",wordsFromCurlOutput.size());
             for( int i = 0; i < wordsFromCurlOutput.size(); i++){
-                jsonObject.put("canBeUsed"+"["+i+"]",TranslateCanBeUsed(wordsFromCurlOutput.get(i).get(1)));
+                jsonObject.put("canBeUsed"+"["+i+"]", translateCanBeUsed(wordsFromCurlOutput.get(i).get(1)));
                 jsonObject.put("variant"+"["+i+"]", StringUtils.htmlToPolishLetter(wordsFromCurlOutput.get(i).get(2)));
                 jsonObject.put("meaning"+"["+i+"]", wrappedDescription(wordsFromCurlOutput.get(i).get(3)));
             }
@@ -68,7 +68,7 @@ private String translateArrayToJSON(List<List<String>> wordsFromCurlOutput ) thr
         return allWrappedWord;
     }
 
-    private Boolean TranslateCanBeUsed(String oneParamOfWordFromCurl){
+    private Boolean translateCanBeUsed(String oneParamOfWordFromCurl){
         return !oneParamOfWordFromCurl.startsWith("niedopuszczalne");
 
     }
diff --git a/src/StringUtils.java b/src/main/java/sjpapi/api/StringUtils.java
similarity index 94%
rename from src/StringUtils.java
rename to src/main/java/sjpapi/api/StringUtils.java
index 4f1cb6f..c8b5b64 100644
--- a/src/StringUtils.java
+++ b/src/main/java/sjpapi/api/StringUtils.java
@@ -57,11 +57,14 @@ public class StringUtils {
         htmlEntities.put("&euro;", "\u20a0");
     }
 
+    private StringUtils() {
+    }
 
     // Function from
     // https://www.rgagnon.com/javadetails/java-0307.html
     public static String unescapeHTML(String source, int start) {
-        int startOfHtmlSpecialCharCombination, closeOfHtmlSpecialCharCombination;
+        int startOfHtmlSpecialCharCombination;
+        int closeOfHtmlSpecialCharCombination;
 
         startOfHtmlSpecialCharCombination = source.indexOf("&", start);
         if (startOfHtmlSpecialCharCombination > -1) {
@@ -86,7 +89,7 @@ public static String htmlToPolishLetter(String htmlWithBadCoding) throws Unsuppo
     }
 
     public static boolean hasSpecyficHTMLTags(String text){
-        String HTML_PATTERN = "<a[^>]*>.+?<\\/a>|<span[^>]*.+?<\\/span>|<p[^>]*.+?<\\/p>";
+        final String HTML_PATTERN = "<a[^>]*>.+?<\\/a>|<span[^>]*.+?<\\/span>|<p[^>]*.+?<\\/p>";
         Pattern pattern = Pattern.compile(HTML_PATTERN);
         Matcher matcher = pattern.matcher(text);
         return matcher.find();
diff --git a/test/CurlReaderTest.java b/src/test/java/CurlReaderTest.java
similarity index 98%
rename from test/CurlReaderTest.java
rename to src/test/java/CurlReaderTest.java
index c1419d9..69190df 100644
--- a/test/CurlReaderTest.java
+++ b/src/test/java/CurlReaderTest.java
@@ -1,16 +1,16 @@
 package sjpapi.api;
 
 import junit.framework.TestCase;
+import sjpapi.api.CurlReader;
 
 import java.io.IOException;
-import java.net.MalformedURLException;
 
 public class CurlReaderTest extends TestCase {
 
     private CurlReader reader = new CurlReader();
 
-    //If this test fails it is means sjp.pl changed something
-    // in the structure of the page, it is possible that
+    //If this test fails, it means sjp.pl changed something
+    // in the structure of the page; it is possible that
     // SjpAPI has stopped working.
     // If it still works, you can ignore this test.
     public void testIsSJPHaveSameSite() throws IOException {
diff --git a/test/CurlValidatorTest.java b/src/test/java/CurlValidatorTest.java
similarity index 97%
rename from test/CurlValidatorTest.java
rename to src/test/java/CurlValidatorTest.java
index 37750a3..eb514cb 100644
--- a/test/CurlValidatorTest.java
+++ b/src/test/java/CurlValidatorTest.java
@@ -1,6 +1,7 @@
 package sjpapi.api;
 
 import junit.framework.TestCase;
+import sjpapi.api.CurlValidator;
 
 public class CurlValidatorTest extends TestCase {
 
diff --git a/test/SjpValidatorTest.java b/src/test/java/SjpValidatorTest.java
similarity index 83%
rename from test/SjpValidatorTest.java
rename to src/test/java/SjpValidatorTest.java
index 5151e86..8d97758 100644
--- a/test/SjpValidatorTest.java
+++ b/src/test/java/SjpValidatorTest.java
@@ -1,10 +1,11 @@
 package sjpapi.api;
 
 import junit.framework.TestCase;
+import sjpapi.api.SjpValidator;
 
 public class SjpValidatorTest extends TestCase {
 
-    private SjpValidator validator = new SjpValidator();
+    private final SjpValidator validator = new SjpValidator();
 
 
     public void testIsCurlHaveH1Tag() {