Use StandardCharsets.UTF_8 (#10113)

18 files changed, 74 insertions, 57 deletions

diff --git a/server/src/main/java/com/vaadin/server/BootstrapHandler.java b/server/src/main/java/com/vaadin/server/BootstrapHandler.java
index 6b43dc3a64..ed6778bf53 100644
--- a/server/src/main/java/com/vaadin/server/BootstrapHandler.java
+++ b/server/src/main/java/com/vaadin/server/BootstrapHandler.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.server;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.BufferedWriter;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
@@ -323,7 +325,8 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
         protected String encodeQueryStringParameterValue(String queryString) {
             String encodedString = null;
             try {
-                encodedString = URLEncoder.encode(queryString, "UTF-8");
+                encodedString = URLEncoder.encode(queryString,
+                        UTF_8.name());
             } catch (UnsupportedEncodingException e) {
                 // should never happen
                 throw new RuntimeException("Could not find UTF-8", e);
@@ -495,7 +498,7 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
         response.setContentType(
                 ApplicationConstants.CONTENT_TYPE_TEXT_HTML_UTF_8);
         try (BufferedWriter writer = new BufferedWriter(
-                new OutputStreamWriter(response.getOutputStream(), "UTF-8"))) {
+                new OutputStreamWriter(response.getOutputStream(), UTF_8))) {
             writer.append(html);
         }
     }
@@ -517,7 +520,8 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
                 "content", ApplicationConstants.CONTENT_TYPE_TEXT_HTML_UTF_8);
 
         // Force IE 11 to use IE 11 mode.
-        head.appendElement("meta").attr("http-equiv", "X-UA-Compatible").attr("content", "IE=11");
+        head.appendElement("meta").attr("http-equiv", "X-UA-Compatible")
+                .attr("content", "IE=11");
 
         Class<? extends UI> uiClass = context.getUIClass();
 
diff --git a/server/src/main/java/com/vaadin/server/ResourceReference.java b/server/src/main/java/com/vaadin/server/ResourceReference.java
index 1ff5f13706..a5a3520eae 100644
--- a/server/src/main/java/com/vaadin/server/ResourceReference.java
+++ b/server/src/main/java/com/vaadin/server/ResourceReference.java
@@ -15,6 +15,8 @@
  */
 package com.vaadin.server;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 
@@ -102,7 +104,7 @@ public class ResourceReference extends URLReference {
 
     static String urlEncode(String filename) {
         try {
-            return URLEncoder.encode(filename, "UTF-8");
+            return URLEncoder.encode(filename, UTF_8.name());
         } catch (UnsupportedEncodingException e) {
             throw new RuntimeException(
                     "UTF-8 charset not available (\"this should never happen\")",
diff --git a/server/src/main/java/com/vaadin/server/VaadinService.java b/server/src/main/java/com/vaadin/server/VaadinService.java
index ba1ecf6740..509b29f9d3 100644
--- a/server/src/main/java/com/vaadin/server/VaadinService.java
+++ b/server/src/main/java/com/vaadin/server/VaadinService.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.server;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.BufferedWriter;
 import java.io.File;
 import java.io.IOException;
@@ -1664,7 +1666,7 @@ public abstract class VaadinService implements Serializable {
 
         final OutputStream out = response.getOutputStream();
         try (PrintWriter outWriter = new PrintWriter(
-                new BufferedWriter(new OutputStreamWriter(out, "UTF-8")))) {
+                new BufferedWriter(new OutputStreamWriter(out, UTF_8)))) {
             outWriter.print(reponseString);
         }
     }
diff --git a/server/src/main/java/com/vaadin/server/VaadinServlet.java b/server/src/main/java/com/vaadin/server/VaadinServlet.java
index 7f2edbfbfd..62bfeb0207 100644
--- a/server/src/main/java/com/vaadin/server/VaadinServlet.java
+++ b/server/src/main/java/com/vaadin/server/VaadinServlet.java
@@ -15,6 +15,8 @@
  */
 package com.vaadin.server;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileInputStream;
@@ -306,12 +308,13 @@ public class VaadinServlet extends HttpServlet implements Constants {
      * @return the created deployment configuration
      *
      * @throws ServletException
-     *            if construction of the {@link Properties} for
-     *            {@link #createDeploymentConfiguration(Properties)} fails
+     *             if construction of the {@link Properties} for
+     *             {@link #createDeploymentConfiguration(Properties)} fails
      *
      * @since 8.2
      */
-    protected DeploymentConfiguration createDeploymentConfiguration() throws ServletException {
+    protected DeploymentConfiguration createDeploymentConfiguration()
+            throws ServletException {
         Properties initParameters = new Properties();
 
         readUiFromEnclosingClass(initParameters);
@@ -363,9 +366,9 @@ public class VaadinServlet extends HttpServlet implements Constants {
      * @return the created vaadin servlet service
      *
      * @throws ServletException
-     *            if creating a deployment configuration fails
+     *             if creating a deployment configuration fails
      * @throws ServiceException
-     *            if creating the vaadin servlet service fails
+     *             if creating the vaadin servlet service fails
      *
      * @since 8.2
      */
@@ -383,7 +386,7 @@ public class VaadinServlet extends HttpServlet implements Constants {
      * @return the created vaadin servlet service
      *
      * @throws ServiceException
-     *            if creating the vaadin servlet service fails
+     *             if creating the vaadin servlet service fails
      *
      * @since 7.0.0
      */
@@ -667,7 +670,7 @@ public class VaadinServlet extends HttpServlet implements Constants {
         final OutputStream out = response.getOutputStream();
         try ( // Set the response type
                 PrintWriter outWriter = new PrintWriter(new BufferedWriter(
-                        new OutputStreamWriter(out, "UTF-8")))) {
+                        new OutputStreamWriter(out, UTF_8)))) {
             outWriter.print(output);
             outWriter.flush();
         }
@@ -1396,7 +1399,8 @@ public class VaadinServlet extends HttpServlet implements Constants {
                 + request.getServerName()
                 + (request.isSecure() && request.getServerPort() == 443
                         || !request.isSecure() && request.getServerPort() == 80
-                                ? "" : ":" + request.getServerPort())
+                                ? ""
+                                : ":" + request.getServerPort())
                 + request.getRequestURI());
         String servletPath = "";
         if (request
diff --git a/server/src/main/java/com/vaadin/server/communication/FileUploadHandler.java b/server/src/main/java/com/vaadin/server/communication/FileUploadHandler.java
index fb02819c23..1323bb1eaa 100644
--- a/server/src/main/java/com/vaadin/server/communication/FileUploadHandler.java
+++ b/server/src/main/java/com/vaadin/server/communication/FileUploadHandler.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.server.communication;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.BufferedWriter;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -226,8 +228,6 @@ public class FileUploadHandler implements RequestHandler {
 
     private static final String CRLF = "\r\n";
 
-    private static final String UTF8 = "UTF-8";
-
     private static final String DASHDASH = "--";
 
     /*
@@ -315,7 +315,7 @@ public class FileUploadHandler implements RequestHandler {
             readByte = stream.read();
         }
         byte[] bytes = bout.toByteArray();
-        return new String(bytes, 0, bytes.length - 1, UTF8);
+        return new String(bytes, 0, bytes.length - 1, UTF_8);
     }
 
     /**
@@ -368,7 +368,7 @@ public class FileUploadHandler implements RequestHandler {
          */
         while (!atStart) {
             String readLine = readLine(inputStream);
-            contentLength -= (readLine.getBytes(UTF8).length + CRLF.length());
+            contentLength -= (readLine.getBytes(UTF_8).length + CRLF.length());
             if (readLine.startsWith("Content-Disposition:")
                     && readLine.indexOf("filename=") > 0) {
                 rawfilename = readLine.replaceAll(".*filename=", "");
@@ -686,7 +686,7 @@ public class FileUploadHandler implements RequestHandler {
                 ApplicationConstants.CONTENT_TYPE_TEXT_HTML_UTF_8);
         try (OutputStream out = response.getOutputStream()) {
             final PrintWriter outWriter = new PrintWriter(
-                    new BufferedWriter(new OutputStreamWriter(out, "UTF-8")));
+                    new BufferedWriter(new OutputStreamWriter(out, UTF_8)));
             outWriter.print("<html><body>download handled</body></html>");
             outWriter.flush();
         }
diff --git a/server/src/main/java/com/vaadin/server/communication/PortletDummyRequestHandler.java b/server/src/main/java/com/vaadin/server/communication/PortletDummyRequestHandler.java
index a3e3fac898..3ff0cf0c65 100644
--- a/server/src/main/java/com/vaadin/server/communication/PortletDummyRequestHandler.java
+++ b/server/src/main/java/com/vaadin/server/communication/PortletDummyRequestHandler.java
@@ -15,6 +15,8 @@
  */
 package com.vaadin.server.communication;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.BufferedWriter;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -61,7 +63,7 @@ public class PortletDummyRequestHandler implements RequestHandler {
         final OutputStream out = ((ResourceResponse) response)
                 .getPortletOutputStream();
         try (PrintWriter outWriter = new PrintWriter(
-                new BufferedWriter(new OutputStreamWriter(out, "UTF-8")))) {
+                new BufferedWriter(new OutputStreamWriter(out, UTF_8)))) {
             outWriter.print("<html><body>dummy page</body></html>");
         }
 
diff --git a/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java b/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java
index 02b0637af8..c2992fc29c 100644
--- a/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java
+++ b/server/src/main/java/com/vaadin/server/communication/UIInitHandler.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.server.communication;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.StringWriter;
@@ -111,7 +113,7 @@ public abstract class UIInitHandler extends SynchronizedRequestHandler {
         // iOS 6 Safari requires this (#9732)
         response.setHeader("Cache-Control", "no-cache");
 
-        byte[] b = json.getBytes("UTF-8");
+        byte[] b = json.getBytes(UTF_8);
         response.setContentLength(b.length);
 
         OutputStream outputStream = response.getOutputStream();
diff --git a/server/src/main/java/com/vaadin/ui/CustomLayout.java b/server/src/main/java/com/vaadin/ui/CustomLayout.java
index 76107d7992..2026038316 100644
--- a/server/src/main/java/com/vaadin/ui/CustomLayout.java
+++ b/server/src/main/java/com/vaadin/ui/CustomLayout.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.ui;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
@@ -113,7 +115,7 @@ public class CustomLayout extends AbstractLayout implements LegacyComponent {
     protected void initTemplateContentsFromInputStream(
             InputStream templateStream) throws IOException {
         BufferedReader reader = new BufferedReader(
-                new InputStreamReader(templateStream, "UTF-8"));
+                new InputStreamReader(templateStream, UTF_8));
         StringBuilder builder = new StringBuilder(BUFFER_SIZE);
         try {
             char[] cbuf = new char[BUFFER_SIZE];
diff --git a/server/src/main/java/com/vaadin/ui/UI.java b/server/src/main/java/com/vaadin/ui/UI.java
index 5c89c7f040..5a8c87f48f 100644
--- a/server/src/main/java/com/vaadin/ui/UI.java
+++ b/server/src/main/java/com/vaadin/ui/UI.java
@@ -16,6 +16,8 @@
 
 package com.vaadin.ui;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.lang.reflect.Method;
@@ -249,7 +251,7 @@ public abstract class UI extends AbstractSingleComponentContainer
                 Design.write((Component) connector, baos);
                 getLogger().info("Design for " + connector
                         + " requested from debug window:\n"
-                        + baos.toString("UTF-8"));
+                        + baos.toString(UTF_8.name()));
             } catch (IOException e) {
                 getLogger().log(Level.WARNING,
                         "Error producing design for " + connector, e);
diff --git a/server/src/main/java/com/vaadin/ui/declarative/Design.java b/server/src/main/java/com/vaadin/ui/declarative/Design.java
index 761ce3c355..65565eb47a 100644
--- a/server/src/main/java/com/vaadin/ui/declarative/Design.java
+++ b/server/src/main/java/com/vaadin/ui/declarative/Design.java
@@ -15,6 +15,8 @@
  */
 package com.vaadin.ui.declarative;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.beans.IntrospectionException;
 import java.io.IOException;
 import java.io.InputStream;
@@ -67,8 +69,6 @@ import com.vaadin.util.ReflectTools;
  */
 public class Design implements Serializable {
 
-    private static final String UTF8 = "UTF-8";
-
     /**
      * Callback for creating instances of a given component class when reading
      * designs. The default implementation, {@link DefaultComponentFactory} will
@@ -392,7 +392,8 @@ public class Design implements Serializable {
      */
     private static Document parse(InputStream html) {
         try {
-            Document doc = Jsoup.parse(html, UTF8, "", Parser.htmlParser());
+            Document doc = Jsoup.parse(html, UTF_8.name(), "",
+                    Parser.htmlParser());
             return doc;
         } catch (IOException e) {
             throw new DesignException("The html document cannot be parsed.");
@@ -808,7 +809,7 @@ public class Design implements Serializable {
         doc.outputSettings().indentAmount(4);
         doc.outputSettings().syntax(Syntax.html);
         doc.outputSettings().prettyPrint(true);
-        outputStream.write(doc.html().getBytes(UTF8));
+        outputStream.write(doc.html().getBytes(UTF_8));
     }
 
     private Design() {
diff --git a/server/src/main/java/com/vaadin/util/EncodeUtil.java b/server/src/main/java/com/vaadin/util/EncodeUtil.java
index 68cdb600e1..19cade5a47 100644
--- a/server/src/main/java/com/vaadin/util/EncodeUtil.java
+++ b/server/src/main/java/com/vaadin/util/EncodeUtil.java
@@ -15,7 +15,7 @@
  */
 package com.vaadin.util;
 
-import java.nio.charset.Charset;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 /**
  * Utilities related to various encoding schemes.
@@ -24,7 +24,6 @@ import java.nio.charset.Charset;
  * @since 7.7.7
  */
 public final class EncodeUtil {
-    private static final Charset UTF8 = Charset.forName("UTF-8");
 
     private EncodeUtil() {
         // Static utils only
@@ -49,7 +48,7 @@ public final class EncodeUtil {
                 // Create string from a single code point
                 String cpAsString = new String(new int[] { cp }, 0, 1);
 
-                appendHexBytes(builder, cpAsString.getBytes(UTF8));
+                appendHexBytes(builder, cpAsString.getBytes(UTF_8));
             }
 
             // Advance to the next code point
diff --git a/server/src/test/java/com/vaadin/tests/design/DeclarativeTestBaseBase.java b/server/src/test/java/com/vaadin/tests/design/DeclarativeTestBaseBase.java
index 323238266e..a3b6fbeeeb 100644
--- a/server/src/test/java/com/vaadin/tests/design/DeclarativeTestBaseBase.java
+++ b/server/src/test/java/com/vaadin/tests/design/DeclarativeTestBaseBase.java
@@ -15,9 +15,10 @@
  */
 package com.vaadin.tests.design;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
-import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -59,21 +60,13 @@ public abstract class DeclarativeTestBaseBase<T extends Component> {
     }
 
     protected T read(String design) {
-        try {
-            return (T) Design
-                    .read(new ByteArrayInputStream(design.getBytes("UTF-8")));
-        } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException(e);
-        }
+        return (T) Design
+                .read(new ByteArrayInputStream(design.getBytes(UTF_8)));
     }
 
     protected DesignContext readAndReturnContext(String design) {
-        try {
-            return Design.read(
-                    new ByteArrayInputStream(design.getBytes("UTF-8")), null);
-        } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException(e);
-        }
+        return Design.read(new ByteArrayInputStream(design.getBytes(UTF_8)),
+                null);
     }
 
     protected String write(T object, boolean writeData) {
@@ -90,7 +83,7 @@ public abstract class DeclarativeTestBaseBase<T extends Component> {
             ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
             context.setRootComponent(object);
             Design.write(context, outputStream);
-            return outputStream.toString("UTF-8");
+            return outputStream.toString(UTF_8.name());
         } catch (Exception e) {
             throw new RuntimeException(e);
         }
diff --git a/server/src/test/java/com/vaadin/tests/design/DesignReadInConstructorTest.java b/server/src/test/java/com/vaadin/tests/design/DesignReadInConstructorTest.java
index 86fb273841..b870e55f13 100644
--- a/server/src/test/java/com/vaadin/tests/design/DesignReadInConstructorTest.java
+++ b/server/src/test/java/com/vaadin/tests/design/DesignReadInConstructorTest.java
@@ -15,6 +15,8 @@
  */
 package com.vaadin.tests.design;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.HashSet;
@@ -44,11 +46,11 @@ public class DesignReadInConstructorTest {
         DesignReadInConstructor dric = new DesignReadInConstructor();
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         Design.write(dric, baos);
-        Document doc = Jsoup.parse(baos.toString("UTF-8"));
+        Document doc = Jsoup.parse(baos.toString(UTF_8.name()));
 
         Document d = Jsoup.parse(
                 getClass().getResourceAsStream("DesignReadInConstructor.html"),
-                "UTF-8", "");
+                UTF_8.name(), "");
         assertJsoupTreeEquals(d.body().child(0), doc.body().child(0));
     }
 
diff --git a/server/src/test/java/com/vaadin/tests/design/FieldNameWhichConflictsWithGettersTest.java b/server/src/test/java/com/vaadin/tests/design/FieldNameWhichConflictsWithGettersTest.java
index 5f60d407bd..91e7e89627 100644
--- a/server/src/test/java/com/vaadin/tests/design/FieldNameWhichConflictsWithGettersTest.java
+++ b/server/src/test/java/com/vaadin/tests/design/FieldNameWhichConflictsWithGettersTest.java
@@ -15,6 +15,8 @@
  */
 package com.vaadin.tests.design;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 
@@ -65,7 +67,7 @@ public class FieldNameWhichConflictsWithGettersTest {
         context.setRootComponent(v);
 
         Design.write(context, baos);
-        String str = baos.toString("UTF-8");
+        String str = baos.toString(UTF_8.name());
 
         Document doc = Jsoup.parse(str);
         Element body = doc.body();
diff --git a/server/src/test/java/com/vaadin/tests/design/InvalidTagNamesTest.java b/server/src/test/java/com/vaadin/tests/design/InvalidTagNamesTest.java
index ac77795b27..98ca82d646 100644
--- a/server/src/test/java/com/vaadin/tests/design/InvalidTagNamesTest.java
+++ b/server/src/test/java/com/vaadin/tests/design/InvalidTagNamesTest.java
@@ -15,8 +15,9 @@
  */
 package com.vaadin.tests.design;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.ByteArrayInputStream;
-import java.io.UnsupportedEncodingException;
 
 import org.junit.Assert;
 import org.junit.Test;
@@ -93,11 +94,6 @@ public class InvalidTagNamesTest {
     }
 
     private Component readDesign(String string) {
-        try {
-            return Design
-                    .read(new ByteArrayInputStream(string.getBytes("UTF-8")));
-        } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException(e);
-        }
+        return Design.read(new ByteArrayInputStream(string.getBytes(UTF_8)));
     }
 }
diff --git a/server/src/test/java/com/vaadin/tests/design/ParseLayoutTest.java b/server/src/test/java/com/vaadin/tests/design/ParseLayoutTest.java
index 56e9a44087..0a0676b8f7 100644
--- a/server/src/test/java/com/vaadin/tests/design/ParseLayoutTest.java
+++ b/server/src/test/java/com/vaadin/tests/design/ParseLayoutTest.java
@@ -15,6 +15,7 @@
  */
 package com.vaadin.tests.design;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.CoreMatchers.nullValue;
@@ -110,7 +111,7 @@ public class ParseLayoutTest {
         String[] expectedPackageNames = { "com.addon.mypackage" };
         int index = 0;
 
-        Document doc = Jsoup.parse(out.toString("UTF-8"));
+        Document doc = Jsoup.parse(out.toString(UTF_8.name()));
         Element head = doc.head();
         for (Node child : head.childNodes()) {
             if ("meta".equals(child.nodeName())) {
diff --git a/server/src/test/java/com/vaadin/tests/design/nested/NestedCustomLayoutsTest.java b/server/src/test/java/com/vaadin/tests/design/nested/NestedCustomLayoutsTest.java
index 341397ff81..7e450cc5f7 100644
--- a/server/src/test/java/com/vaadin/tests/design/nested/NestedCustomLayoutsTest.java
+++ b/server/src/test/java/com/vaadin/tests/design/nested/NestedCustomLayoutsTest.java
@@ -15,6 +15,7 @@
  */
 package com.vaadin.tests.design.nested;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.greaterThan;
@@ -57,7 +58,7 @@ public class NestedCustomLayoutsTest {
         ByteArrayOutputStream out = new ByteArrayOutputStream();
 
         Design.write(rootLayout, out);
-        Document doc = Jsoup.parse(out.toString("UTF-8"));
+        Document doc = Jsoup.parse(out.toString(UTF_8.name()));
 
         assertThat(doc.head().child(0).attr("name"), is("package-mapping"));
         assertThat(doc.head().child(0).attr("content"), is(PACKAGE_MAPPING));
diff --git a/server/src/test/java/com/vaadin/tests/server/component/gridlayout/GridLayoutDeclarativeTest.java b/server/src/test/java/com/vaadin/tests/server/component/gridlayout/GridLayoutDeclarativeTest.java
index b641f3b249..0ca92e4ed5 100644
--- a/server/src/test/java/com/vaadin/tests/server/component/gridlayout/GridLayoutDeclarativeTest.java
+++ b/server/src/test/java/com/vaadin/tests/server/component/gridlayout/GridLayoutDeclarativeTest.java
@@ -15,6 +15,8 @@
  */
 package com.vaadin.tests.server.component.gridlayout;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -330,7 +332,7 @@ public class GridLayoutDeclarativeTest
                 + "<row><column><vaadin-grid-layout _id=\"marginBottomComponent\" margin-bottom></vaadin-grid-layout></column></row>"
                 + "</vaadin-grid-layout>";
         DesignContext context = Design
-                .read(new ByteArrayInputStream(design.getBytes("UTF-8")), null);
+                .read(new ByteArrayInputStream(design.getBytes(UTF_8)), null);
         Assert.assertEquals(null, context.getCustomAttributes(
                 context.getComponentByLocalId("marginComponent")));
         Assert.assertEquals(null, context.getCustomAttributes(
@@ -352,7 +354,7 @@ public class GridLayoutDeclarativeTest
                 + "<my-preconfigured-grid-layout></my-preconfigured-grid-layout>";
 
         PreconfiguredGridLayout myLayout = (PreconfiguredGridLayout) Design
-                .read(new ByteArrayInputStream(design.getBytes("UTF-8")));
+                .read(new ByteArrayInputStream(design.getBytes(UTF_8)));
         Assert.assertEquals(2, myLayout.getRows());
         Assert.assertEquals(2, myLayout.getColumns());
     }