Use StandardCharsets

core/src/main/java/hudson/Main.java

@@ -25,6 +25,7 @@ package hudson;
 
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
 import jenkins.util.SystemProperties;
@@ -97,7 +98,7 @@ public class Main {
 
         // check for authentication info
         String auth = new URL(home).getUserInfo();
-        if(auth != null) auth = "Basic " + new Base64Encoder().encode(auth.getBytes("UTF-8"));
+        if(auth != null) auth = "Basic " + new Base64Encoder().encode(auth.getBytes(StandardCharsets.UTF_8));
 
         {// check if the home is set correctly
             HttpURLConnection con = open(new URL(home));
@@ -143,7 +144,7 @@ public class Main {
         try {
             int ret;
             try (OutputStream os = Files.newOutputStream(tmpFile.toPath());
-                 Writer w = new OutputStreamWriter(os,"UTF-8")) {
+                 Writer w = new OutputStreamWriter(os, StandardCharsets.UTF_8)) {
                 w.write("<?xml version='1.1' encoding='UTF-8'?>");
                 w.write("<run><log encoding='hexBinary' content-encoding='"+Charset.defaultCharset().name()+"'>");
                 w.flush();