Fix Checkstyle and Modernizer warnings

pom.xml

@@ -345,6 +345,9 @@
         </executions>
         <configuration>
           <javaVersion>${java.version}</javaVersion>
+          <exclusions>
+            <exclusion>com/google/common/base/Supplier</exclusion>
+          </exclusions>
         </configuration>
       </plugin>
       <plugin>
@@ -395,9 +398,9 @@
       </exclusions>
     </dependency>
     <dependency>
-        <groupId>com.amazonaws</groupId>
-        <artifactId>aws-java-sdk-sts</artifactId>
-        <version>1.12.261</version>
+      <groupId>com.amazonaws</groupId>
+      <artifactId>aws-java-sdk-sts</artifactId>
+      <version>1.12.261</version>
     </dependency>
     <dependency>
       <groupId>args4j</groupId>

src/main/java/org/gaul/s3proxy/Main.java

@@ -40,11 +40,11 @@ import com.amazonaws.auth.AWSCredentialsProvider;
 import com.amazonaws.auth.AWSSessionCredentials;
 import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
 import com.google.common.base.Strings;
+import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableBiMap;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.io.MoreFiles;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
-import com.google.common.base.Supplier;
 
 import org.jclouds.Constants;
 import org.jclouds.ContextBuilder;
@@ -54,11 +54,11 @@ import org.jclouds.blobstore.BlobStore;
 import org.jclouds.blobstore.BlobStoreContext;
 import org.jclouds.concurrent.DynamicExecutors;
 import org.jclouds.concurrent.config.ExecutorServiceModule;
+import org.jclouds.domain.Credentials;
 import org.jclouds.location.reference.LocationConstants;
 import org.jclouds.logging.slf4j.config.SLF4JLoggingModule;
 import org.jclouds.openstack.swift.v1.blobstore.RegionScopedBlobStoreContext;
 import org.jclouds.s3.domain.ObjectMetadata.StorageClass;
-import org.jclouds.domain.Credentials;
 import org.kohsuke.args4j.CmdLineException;
 import org.kohsuke.args4j.CmdLineParser;
 import org.kohsuke.args4j.Option;
@@ -392,7 +392,7 @@ public final class Main {
         }
 
         if ((identity.isEmpty() || credential.isEmpty()) && provider.equals("aws-s3")) {
-            Supplier<Credentials> credentialsSupplier = new Supplier<Credentials>() {
+            var credentialsSupplier = new Supplier<Credentials>() {
                 @Override
                 public Credentials get() {
                     AWSCredentialsProvider authChain = DefaultAWSCredentialsProviderChain.getInstance();