diff --git a/src/main/java/org/elasticsearch/license/core/ESLicense.java b/src/main/java/org/elasticsearch/license/core/ESLicense.java
index 45ad44cee62..a0936ac963f 100644
--- a/src/main/java/org/elasticsearch/license/core/ESLicense.java
+++ b/src/main/java/org/elasticsearch/license/core/ESLicense.java
@@ -7,10 +7,11 @@ package org.elasticsearch.license.core;
 
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.common.xcontent.*;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
-import java.util.*;
+import java.util.HashMap;
+import java.util.Map;
 
 public class ESLicense implements Comparable<ESLicense> {
 
diff --git a/src/main/java/org/elasticsearch/license/core/ESLicenses.java b/src/main/java/org/elasticsearch/license/core/ESLicenses.java
index f6174721fb6..21825c4d705 100644
--- a/src/main/java/org/elasticsearch/license/core/ESLicenses.java
+++ b/src/main/java/org/elasticsearch/license/core/ESLicenses.java
@@ -5,17 +5,13 @@
  */
 package org.elasticsearch.license.core;
 
-import org.elasticsearch.common.bytes.BytesArray;
-import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
-import java.nio.charset.Charset;
 import java.util.*;
 
 public class ESLicenses {
@@ -31,7 +27,7 @@ public class ESLicenses {
     }
 
     public static Set<ESLicense> fromSource(String content) throws IOException {
-        return fromSource(content.getBytes(Charset.forName("UTF-8")));
+        return fromSource(content.getBytes(LicensesCharset.UTF_8));
     }
 
     public static Set<ESLicense> fromSource(byte[] bytes) throws IOException {
@@ -41,6 +37,7 @@ public class ESLicenses {
     private static Set<ESLicense> fromXContent(XContentParser parser) throws IOException {
         Set<ESLicense> esLicenses = new HashSet<>();
         final Map<String, Object> licensesMap = parser.mapAndClose();
+        @SuppressWarnings("unchecked")
         final List<Map<String, Object>> licenseMaps = (ArrayList<Map<String, Object>>)licensesMap.get("licenses");
         for (Map<String, Object> licenseMap : licenseMaps) {
             final ESLicense esLicense = ESLicense.fromXContent(licenseMap);
diff --git a/src/main/java/org/elasticsearch/license/core/LicensesCharset.java b/src/main/java/org/elasticsearch/license/core/LicensesCharset.java
new file mode 100644
index 00000000000..04efbb18a87
--- /dev/null
+++ b/src/main/java/org/elasticsearch/license/core/LicensesCharset.java
@@ -0,0 +1,17 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.license.core;
+
+import java.nio.charset.Charset;
+
+public class LicensesCharset {
+
+    /**
+     * All operations in should use the universal UTF-8 character set.
+     */
+    public static final Charset UTF_8 = Charset.forName("UTF-8");
+
+}
diff --git a/src/main/java/org/elasticsearch/license/licensor/ESLicenseSigner.java b/src/main/java/org/elasticsearch/license/licensor/ESLicenseSigner.java
index ab2cf52150d..d9f82a8df91 100644
--- a/src/main/java/org/elasticsearch/license/licensor/ESLicenseSigner.java
+++ b/src/main/java/org/elasticsearch/license/licensor/ESLicenseSigner.java
@@ -13,13 +13,12 @@ import net.nicholaswilliams.java.licensing.exception.KeyNotFoundException;
 import net.nicholaswilliams.java.licensing.licensor.LicenseCreator;
 import net.nicholaswilliams.java.licensing.licensor.LicenseCreatorProperties;
 import org.apache.commons.codec.binary.Base64;
-import org.elasticsearch.common.collect.ImmutableMap;
 import org.elasticsearch.common.collect.ImmutableSet;
-import org.elasticsearch.license.core.*;
+import org.elasticsearch.license.core.ESLicense;
+import org.elasticsearch.license.core.LicensesCharset;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
-import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -105,7 +104,7 @@ public class ESLicenseSigner {
         final byte[] licenseSignature = licenseCreator.signAndSerializeLicense(license);
         final byte[] hash = Hasher.hash(Base64.encodeBase64String(
                         Files.readAllBytes(publicKeyPath))
-        ).getBytes(Charset.forName("UTF-8"));
+        ).getBytes(LicensesCharset.UTF_8);
         int headerLength = MAGIC_LENGTH + hash.length + 4 + 4;
         byte[] bytes = new byte[headerLength + licenseSignature.length];
 
diff --git a/src/main/java/org/elasticsearch/license/licensor/LicenseSpec.java b/src/main/java/org/elasticsearch/license/licensor/LicenseSpec.java
index b2655590859..74e2c0f815e 100644
--- a/src/main/java/org/elasticsearch/license/licensor/LicenseSpec.java
+++ b/src/main/java/org/elasticsearch/license/licensor/LicenseSpec.java
@@ -8,14 +8,14 @@ package org.elasticsearch.license.licensor;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.license.core.DateUtils;
+import org.elasticsearch.license.core.LicensesCharset;
 
 import java.io.IOException;
-import java.nio.charset.Charset;
 import java.text.ParseException;
 import java.util.*;
 
-import static org.elasticsearch.license.core.ESLicense.Type;
 import static org.elasticsearch.license.core.ESLicense.SubscriptionType;
+import static org.elasticsearch.license.core.ESLicense.Type;
 
 public class LicenseSpec {
     final String uid;
@@ -43,7 +43,7 @@ public class LicenseSpec {
     }
 
 
-    public static class Builder {
+    private static class Builder {
         private String uid;
         private String issuer;
         private String issuedTo;
@@ -104,6 +104,7 @@ public class LicenseSpec {
             if (uid == null) {
                 uid = UUID.randomUUID().toString();
             }
+            //TODO: verify params
             return new LicenseSpec(uid, issuer, issuedTo, issueDate, type, subscriptionType,
                     feature ,expiryDate, maxNodes);
         }
@@ -128,7 +129,7 @@ public class LicenseSpec {
     }
 
     public static Set<LicenseSpec> fromSource(String content) throws IOException, ParseException {
-        return fromSource(content.getBytes(Charset.forName("UTF-8")));
+        return fromSource(content.getBytes(LicensesCharset.UTF_8));
     }
 
     public static Set<LicenseSpec> fromSource(byte[] bytes) throws IOException, ParseException {
@@ -138,6 +139,7 @@ public class LicenseSpec {
     private static Set<LicenseSpec> fromXContents(XContentParser parser) throws IOException, ParseException {
         Set<LicenseSpec> licenseSpecs = new HashSet<>();
         final Map<String, Object> licenseSpecMap = parser.mapAndClose();
+        @SuppressWarnings("unchecked")
         final List<Map<String, Object>> licenseSpecDefinitions = (ArrayList<Map<String, Object>>)licenseSpecMap.get("licenses");
         for (Map<String, Object> licenseSpecDef : licenseSpecDefinitions) {
             final LicenseSpec licenseSpec = fromXContent(licenseSpecDef);
diff --git a/src/main/java/org/elasticsearch/license/plugin/LicenseModule.java b/src/main/java/org/elasticsearch/license/plugin/LicenseModule.java
index d0f08b0c525..1ace3805f4f 100644
--- a/src/main/java/org/elasticsearch/license/plugin/LicenseModule.java
+++ b/src/main/java/org/elasticsearch/license/plugin/LicenseModule.java
@@ -7,8 +7,6 @@ package org.elasticsearch.license.plugin;
 
 import org.elasticsearch.common.inject.AbstractModule;
 import org.elasticsearch.common.inject.Scopes;
-import org.elasticsearch.license.manager.ESLicenseManager;
-import org.elasticsearch.license.plugin.core.LicensesManagerService;
 import org.elasticsearch.license.plugin.core.LicensesService;
 
 public class LicenseModule extends AbstractModule {
diff --git a/src/main/java/org/elasticsearch/license/plugin/LicensePlugin.java b/src/main/java/org/elasticsearch/license/plugin/LicensePlugin.java
index 66a177108ba..e562345062e 100644
--- a/src/main/java/org/elasticsearch/license/plugin/LicensePlugin.java
+++ b/src/main/java/org/elasticsearch/license/plugin/LicensePlugin.java
@@ -6,7 +6,6 @@
 package org.elasticsearch.license.plugin;
 
 import org.elasticsearch.action.ActionModule;
-import org.elasticsearch.action.admin.cluster.ClusterAction;
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.collect.ImmutableSet;
@@ -22,10 +21,10 @@ import org.elasticsearch.license.plugin.action.get.TransportGetLicenseAction;
 import org.elasticsearch.license.plugin.action.put.PutLicenseAction;
 import org.elasticsearch.license.plugin.action.put.TransportPutLicenseAction;
 import org.elasticsearch.license.plugin.core.LicensesMetaData;
+import org.elasticsearch.license.plugin.core.LicensesService;
 import org.elasticsearch.license.plugin.rest.RestDeleteLicenseAction;
 import org.elasticsearch.license.plugin.rest.RestGetLicenseAction;
 import org.elasticsearch.license.plugin.rest.RestPutLicenseAction;
-import org.elasticsearch.license.plugin.core.LicensesService;
 import org.elasticsearch.plugins.AbstractPlugin;
 import org.elasticsearch.rest.RestModule;
 
diff --git a/src/main/java/org/elasticsearch/license/plugin/action/delete/DeleteLicenseRequest.java b/src/main/java/org/elasticsearch/license/plugin/action/delete/DeleteLicenseRequest.java
index 8d7c11daf7b..66aeb014370 100644
--- a/src/main/java/org/elasticsearch/license/plugin/action/delete/DeleteLicenseRequest.java
+++ b/src/main/java/org/elasticsearch/license/plugin/action/delete/DeleteLicenseRequest.java
@@ -5,13 +5,10 @@
  */
 package org.elasticsearch.license.plugin.action.delete;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.support.master.AcknowledgedRequest;
-import org.elasticsearch.action.support.master.MasterNodeReadOperationRequest;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.license.core.ESLicenses;
 
 import java.io.IOException;
 import java.util.Arrays;
diff --git a/src/main/java/org/elasticsearch/license/plugin/action/delete/TransportDeleteLicenseAction.java b/src/main/java/org/elasticsearch/license/plugin/action/delete/TransportDeleteLicenseAction.java
index 0af0e1dc300..5c08c9f115d 100644
--- a/src/main/java/org/elasticsearch/license/plugin/action/delete/TransportDeleteLicenseAction.java
+++ b/src/main/java/org/elasticsearch/license/plugin/action/delete/TransportDeleteLicenseAction.java
@@ -17,9 +17,6 @@ import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.license.plugin.core.LicensesManagerService;
-import org.elasticsearch.license.plugin.core.LicensesService;
-import org.elasticsearch.node.Node;
-import org.elasticsearch.node.internal.InternalNode;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
diff --git a/src/main/java/org/elasticsearch/license/plugin/core/LicensesMetaData.java b/src/main/java/org/elasticsearch/license/plugin/core/LicensesMetaData.java
index fba01c3aae4..2cc6578e945 100644
--- a/src/main/java/org/elasticsearch/license/plugin/core/LicensesMetaData.java
+++ b/src/main/java/org/elasticsearch/license/plugin/core/LicensesMetaData.java
@@ -14,7 +14,9 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
-import java.util.*;
+import java.util.EnumSet;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * Contains metadata about registered licenses
diff --git a/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicenseUtils.java b/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicenseUtils.java
index 113fc18f981..49a4cedb229 100644
--- a/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicenseUtils.java
+++ b/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicenseUtils.java
@@ -6,16 +6,9 @@
 package org.elasticsearch.license.plugin.core.trial;
 
 import org.apache.commons.codec.binary.Base64;
-import org.elasticsearch.common.collect.ImmutableMap;
-import org.elasticsearch.common.io.stream.StreamInput;
-import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.license.core.ESLicenses;
+import org.elasticsearch.license.core.LicensesCharset;
 
-import java.io.IOException;
 import java.nio.ByteBuffer;
-import java.nio.charset.Charset;
-import java.util.HashSet;
-import java.util.Map;
 import java.util.Set;
 
 import static org.elasticsearch.license.plugin.core.trial.TrialLicensesBuilder.trialLicensesBuilder;
@@ -29,17 +22,17 @@ public class TrialLicenseUtils {
         int uidLen = byteBuffer.getInt();
         byte[] uidBytes = new byte[uidLen];
         byteBuffer.get(uidBytes);
-        String uid = new String(uidBytes, Charset.forName("UTF-8"));
+        String uid = new String(uidBytes, LicensesCharset.UTF_8);
 
         int issuedToLen = byteBuffer.getInt();
         byte[] issuedToBytes = new byte[issuedToLen];
         byteBuffer.get(issuedToBytes);
-        String issuedTo = new String(issuedToBytes, Charset.forName("UTF-8"));
+        String issuedTo = new String(issuedToBytes, LicensesCharset.UTF_8);
 
         int featureLen = byteBuffer.getInt();
         byte[] featureBytes = new byte[featureLen];
         byteBuffer.get(featureBytes);
-        String feature = new String(featureBytes, Charset.forName("UTF-8"));
+        String feature = new String(featureBytes, LicensesCharset.UTF_8);
 
         int maxNodes = byteBuffer.getInt();
         long issueDate = byteBuffer.getLong();
@@ -56,9 +49,9 @@ public class TrialLicenseUtils {
     }
 
     public static String toEncodedTrialLicense(TrialLicenses.TrialLicense trialLicense) {
-        byte[] uidBytes = trialLicense.uid().getBytes(Charset.forName("UTF-8"));
-        byte[] featureBytes = trialLicense.feature().getBytes(Charset.forName("UTF-8"));
-        byte[] issuedToBytes = trialLicense.issuedTo().getBytes(Charset.forName("UTF-8"));
+        byte[] uidBytes = trialLicense.uid().getBytes(LicensesCharset.UTF_8);
+        byte[] featureBytes = trialLicense.feature().getBytes(LicensesCharset.UTF_8);
+        byte[] issuedToBytes = trialLicense.issuedTo().getBytes(LicensesCharset.UTF_8);
 
         // uid len + uid bytes + issuedTo len + issuedTo bytes + feature bytes length + feature bytes + maxNodes + issueDate + expiryDate
         int len = 4 + uidBytes.length + 4 + issuedToBytes.length + 4 + featureBytes.length + 4 + 8 + 8;
diff --git a/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicensesBuilder.java b/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicensesBuilder.java
index 336d035b540..56039ce9367 100644
--- a/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicensesBuilder.java
+++ b/src/main/java/org/elasticsearch/license/plugin/core/trial/TrialLicensesBuilder.java
@@ -9,7 +9,9 @@ import org.elasticsearch.common.collect.ImmutableMap;
 import org.elasticsearch.license.core.DateUtils;
 import org.elasticsearch.license.core.ESLicense;
 
-import java.util.*;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.UUID;
 
 import static org.elasticsearch.license.plugin.core.trial.TrialLicenses.TrialLicense;
 
diff --git a/src/test/java/org/elasticsearch/license/TestUtils.java b/src/test/java/org/elasticsearch/license/TestUtils.java
index e4bf26131d7..010d4488b6b 100644
--- a/src/test/java/org/elasticsearch/license/TestUtils.java
+++ b/src/test/java/org/elasticsearch/license/TestUtils.java
@@ -15,7 +15,6 @@ import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.text.ParseException;
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 
diff --git a/src/test/java/org/elasticsearch/license/plugin/LicenseTransportTests.java b/src/test/java/org/elasticsearch/license/plugin/LicenseTransportTests.java
index f0dfce1e319..17d57850a42 100644
--- a/src/test/java/org/elasticsearch/license/plugin/LicenseTransportTests.java
+++ b/src/test/java/org/elasticsearch/license/plugin/LicenseTransportTests.java
@@ -11,7 +11,8 @@ import org.elasticsearch.common.collect.ImmutableSet;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.license.TestUtils;
-import org.elasticsearch.license.core.*;
+import org.elasticsearch.license.core.ESLicense;
+import org.elasticsearch.license.core.ESLicenses;
 import org.elasticsearch.license.manager.Utils;
 import org.elasticsearch.license.plugin.action.delete.DeleteLicenseRequestBuilder;
 import org.elasticsearch.license.plugin.action.delete.DeleteLicenseResponse;
diff --git a/src/test/java/org/elasticsearch/license/plugin/LicensesServiceTests.java b/src/test/java/org/elasticsearch/license/plugin/LicensesServiceTests.java
index 75aff11d21a..66391e16f5c 100644
--- a/src/test/java/org/elasticsearch/license/plugin/LicensesServiceTests.java
+++ b/src/test/java/org/elasticsearch/license/plugin/LicensesServiceTests.java
@@ -15,7 +15,8 @@ import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.license.TestUtils;
-import org.elasticsearch.license.core.*;
+import org.elasticsearch.license.core.ESLicense;
+import org.elasticsearch.license.core.ESLicenses;
 import org.elasticsearch.license.manager.ESLicenseManager;
 import org.elasticsearch.license.manager.Utils;
 import org.elasticsearch.license.plugin.action.put.PutLicenseRequest;