Merge PR #392: [WIP] Update jmx-metrics module to follow style guide

Author: trask

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/ClientCallbackHandler.java

@@ -13,7 +13,7 @@
 import javax.security.auth.callback.UnsupportedCallbackException;
 import javax.security.sasl.RealmCallback;
 
-public class ClientCallbackHandler implements CallbackHandler {
+public final class ClientCallbackHandler implements CallbackHandler {
   private final String username;
   @Nullable private final char[] password;
   private final String realm;

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/ConfigurationException.java

@@ -5,7 +5,7 @@
 
 package io.opentelemetry.contrib.jmxmetrics;
 
-public class ConfigurationException extends RuntimeException {
+public final class ConfigurationException extends RuntimeException {
   private static final long serialVersionUID = 0L;
 
   public ConfigurationException(final String message, final Throwable cause) {

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/GroovyMetricEnvironment.java

@@ -37,7 +37,7 @@
 import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 
-public class GroovyMetricEnvironment {
+public final class GroovyMetricEnvironment {
   private final SdkMeterProvider meterProvider;
   private final Meter meter;
 

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/GroovyRunner.java

@@ -29,7 +29,7 @@
 import java.util.logging.Logger;
 import org.codehaus.groovy.control.CompilationFailedException;
 
-public class GroovyRunner {
+public final class GroovyRunner {
   private static final Logger logger = Logger.getLogger(GroovyRunner.class.getName());
 
   private final List<Script> scripts;

jmx-metrics/src/main/groovy/io/opentelemetry/contrib/jmxmetrics/JmxClient.java

@@ -22,7 +22,7 @@
 import javax.management.remote.JMXConnector;
 import javax.management.remote.JMXServiceURL;
 
-public class JmxClient {
+public final class JmxClient {
   private static final Logger logger = Logger.getLogger(JmxClient.class.getName());
 
   private final JMXServiceURL url;