diff --git a/appengine/java/com/google/auth/appengine/AppEngineCredentials.java b/appengine/java/com/google/auth/appengine/AppEngineCredentials.java
index dbae97052..4d4b6009d 100644
--- a/appengine/java/com/google/auth/appengine/AppEngineCredentials.java
+++ b/appengine/java/com/google/auth/appengine/AppEngineCredentials.java
@@ -56,11 +56,7 @@
  */
 public class AppEngineCredentials extends GoogleCredentials implements ServiceAccountSigner {
 
-  private static final Logger LOGGER = Logger.getLogger(AppEngineCredentials.class.getName());
-  private static final String APPLICATION_DEFAULT_CREDENTIALS_WARNING =
-      "You are attempting to "
-          + "fetch Application Default Credentials from com.google.auth.appengine.AppEngineCredentials."
-          + " This method will not return a com.google.auth.appengine.AppEngineCredentials instance.";
+  private static final Logger logger = Logger.getLogger(AppEngineCredentials.class.getName());
   private static final long serialVersionUID = -2627708355455064660L;
 
   private final String appIdentityServiceClassName;
@@ -75,7 +71,10 @@ public class AppEngineCredentials extends GoogleCredentials implements ServiceAc
    */
   @Deprecated
   public static GoogleCredentials getApplicationDefault() throws IOException {
-    LOGGER.warning(APPLICATION_DEFAULT_CREDENTIALS_WARNING);
+    logger.warning(
+        "You are attempting to "
+            + "fetch Application Default Credentials from com.google.auth.appengine.AppEngineCredentials."
+            + " This method will not return a com.google.auth.appengine.AppEngineCredentials instance.");
     return GoogleCredentials.getApplicationDefault();
   }
 
@@ -86,7 +85,10 @@ public static GoogleCredentials getApplicationDefault() throws IOException {
   @Deprecated
   public static GoogleCredentials getApplicationDefault(HttpTransportFactory transportFactory)
       throws IOException {
-    LOGGER.warning(APPLICATION_DEFAULT_CREDENTIALS_WARNING);
+    logger.warning(
+        "You are attempting to fetch "
+            + "Application Default Credentials from com.google.auth.appengine.AppEngineCredentials. "
+            + "This method does not return a com.google.auth.appengine.AppEngineCredentials instance.");
     return GoogleCredentials.getApplicationDefault(transportFactory);
   }
 
diff --git a/oauth2_http/java/com/google/auth/oauth2/GoogleCredentials.java b/oauth2_http/java/com/google/auth/oauth2/GoogleCredentials.java
index c32e72f47..c9ea810fb 100644
--- a/oauth2_http/java/com/google/auth/oauth2/GoogleCredentials.java
+++ b/oauth2_http/java/com/google/auth/oauth2/GoogleCredentials.java
@@ -39,6 +39,7 @@
 import com.google.common.collect.ImmutableList;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -153,7 +154,7 @@ public static GoogleCredentials fromStream(
     JsonFactory jsonFactory = OAuth2Utils.JSON_FACTORY;
     JsonObjectParser parser = new JsonObjectParser(jsonFactory);
     GenericJson fileContents =
-        parser.parseAndClose(credentialsStream, OAuth2Utils.UTF_8, GenericJson.class);
+        parser.parseAndClose(credentialsStream, StandardCharsets.UTF_8, GenericJson.class);
 
     String fileType = (String) fileContents.get("type");
     if (fileType == null) {
diff --git a/oauth2_http/java/com/google/auth/oauth2/JwtProvider.java b/oauth2_http/java/com/google/auth/oauth2/JwtProvider.java
index eadee9600..7a2352ac5 100644
--- a/oauth2_http/java/com/google/auth/oauth2/JwtProvider.java
+++ b/oauth2_http/java/com/google/auth/oauth2/JwtProvider.java
@@ -40,8 +40,7 @@ public interface JwtProvider {
   /**
    * Returns a new JwtCredentials instance with modified claims.
    *
-   * @param newClaims new claims. Any unspecified claim fields will default to the the current
-   *     values.
+   * @param newClaims new claims. Any unspecified claim fields default to the current values.
    * @return new credentials
    */
   JwtCredentials jwtWithClaims(JwtClaims newClaims);
diff --git a/oauth2_http/java/com/google/auth/oauth2/OAuth2Utils.java b/oauth2_http/java/com/google/auth/oauth2/OAuth2Utils.java
index f23232cca..54e6bb941 100644
--- a/oauth2_http/java/com/google/auth/oauth2/OAuth2Utils.java
+++ b/oauth2_http/java/com/google/auth/oauth2/OAuth2Utils.java
@@ -49,7 +49,6 @@
 import java.io.OutputStream;
 import java.math.BigDecimal;
 import java.net.URI;
-import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Collection;
 import java.util.Map;
@@ -68,8 +67,6 @@ class OAuth2Utils {
 
   static final JsonFactory JSON_FACTORY = GsonFactory.getDefaultInstance();
 
-  static final Charset UTF_8 = Charset.forName("UTF-8");
-
   private static String VALUE_NOT_FOUND_MESSAGE = "%sExpected value %s not found.";
   private static String VALUE_WRONG_TYPE_MESSAGE = "%sExpected %s value %s of wrong type.";
 
diff --git a/oauth2_http/java/com/google/auth/oauth2/ServiceAccountCredentials.java b/oauth2_http/java/com/google/auth/oauth2/ServiceAccountCredentials.java
index b0d580336..64b5d0af2 100644
--- a/oauth2_http/java/com/google/auth/oauth2/ServiceAccountCredentials.java
+++ b/oauth2_http/java/com/google/auth/oauth2/ServiceAccountCredentials.java
@@ -66,6 +66,7 @@
 import java.io.StringReader;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.nio.charset.StandardCharsets;
 import java.security.GeneralSecurityException;
 import java.security.InvalidKeyException;
 import java.security.KeyFactory;
@@ -390,7 +391,7 @@ public static ServiceAccountCredentials fromStream(
     JsonFactory jsonFactory = OAuth2Utils.JSON_FACTORY;
     JsonObjectParser parser = new JsonObjectParser(jsonFactory);
     GenericJson fileContents =
-        parser.parseAndClose(credentialsStream, OAuth2Utils.UTF_8, GenericJson.class);
+        parser.parseAndClose(credentialsStream, StandardCharsets.UTF_8, GenericJson.class);
 
     String fileType = (String) fileContents.get("type");
     if (fileType == null) {
diff --git a/oauth2_http/java/com/google/auth/oauth2/ServiceAccountJwtAccessCredentials.java b/oauth2_http/java/com/google/auth/oauth2/ServiceAccountJwtAccessCredentials.java
index 6a5805ef4..707b657a7 100644
--- a/oauth2_http/java/com/google/auth/oauth2/ServiceAccountJwtAccessCredentials.java
+++ b/oauth2_http/java/com/google/auth/oauth2/ServiceAccountJwtAccessCredentials.java
@@ -54,6 +54,7 @@
 import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.net.URI;
+import java.nio.charset.StandardCharsets;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
 import java.security.PrivateKey;
@@ -250,7 +251,7 @@ public static ServiceAccountJwtAccessCredentials fromStream(
     JsonFactory jsonFactory = OAuth2Utils.JSON_FACTORY;
     JsonObjectParser parser = new JsonObjectParser(jsonFactory);
     GenericJson fileContents =
-        parser.parseAndClose(credentialsStream, OAuth2Utils.UTF_8, GenericJson.class);
+        parser.parseAndClose(credentialsStream, StandardCharsets.UTF_8, GenericJson.class);
 
     String fileType = (String) fileContents.get("type");
     if (fileType == null) {
diff --git a/oauth2_http/java/com/google/auth/oauth2/UserCredentials.java b/oauth2_http/java/com/google/auth/oauth2/UserCredentials.java
index bd8dcfd61..b8a05bcd1 100644
--- a/oauth2_http/java/com/google/auth/oauth2/UserCredentials.java
+++ b/oauth2_http/java/com/google/auth/oauth2/UserCredentials.java
@@ -32,7 +32,6 @@
 package com.google.auth.oauth2;
 
 import static com.google.auth.oauth2.OAuth2Utils.JSON_FACTORY;
-import static com.google.auth.oauth2.OAuth2Utils.UTF_8;
 import static com.google.common.base.MoreObjects.firstNonNull;
 
 import com.google.api.client.http.GenericUrl;
@@ -52,6 +51,7 @@
 import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.net.URI;
+import java.nio.charset.StandardCharsets;
 import java.util.Date;
 import java.util.List;
 import java.util.Map;
@@ -167,7 +167,7 @@ public static UserCredentials fromStream(
     JsonFactory jsonFactory = JSON_FACTORY;
     JsonObjectParser parser = new JsonObjectParser(jsonFactory);
     GenericJson fileContents =
-        parser.parseAndClose(credentialsStream, OAuth2Utils.UTF_8, GenericJson.class);
+        parser.parseAndClose(credentialsStream, StandardCharsets.UTF_8, GenericJson.class);
 
     String fileType = (String) fileContents.get("type");
     if (fileType == null) {
@@ -263,7 +263,7 @@ private InputStream getUserCredentialsStream() throws IOException {
     }
     json.setFactory(JSON_FACTORY);
     String text = json.toPrettyString();
-    return new ByteArrayInputStream(text.getBytes(UTF_8));
+    return new ByteArrayInputStream(text.getBytes(StandardCharsets.UTF_8));
   }
 
   /**