diff --git a/build.gradle b/build.gradle
index 8820e72..3a20404 100644
--- a/build.gradle
+++ b/build.gradle
@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.3'
+        classpath 'com.android.tools.build:gradle:3.6.1'
         classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.8.4'
     }
 }
diff --git a/gradle.properties b/gradle.properties
index aac7c9b..c7fb972 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -15,3 +15,5 @@ org.gradle.jvmargs=-Xmx1536m
 # This option should only be used with decoupled projects. More details, visit
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
 # org.gradle.parallel=true
+
+android.useAndroidX=true
\ No newline at end of file
diff --git a/lib/build.gradle b/lib/build.gradle
index 2052d25..5eccd55 100644
--- a/lib/build.gradle
+++ b/lib/build.gradle
@@ -39,7 +39,10 @@ dependencies {
 
     testImplementation 'junit:junit:4.13'
     testImplementation 'org.hamcrest:java-hamcrest:2.0.0.0'
-    testImplementation 'org.robolectric:robolectric:4.3.1'
+    testImplementation('org.robolectric:robolectric:4.3.1') {
+        // https://github.com/robolectric/robolectric/issues/5245
+        exclude group: 'com.google.auto.service', module: 'auto-service'
+    }
     testImplementation 'org.mockito:mockito-core:3.2.4'
 }
 
diff --git a/lib/src/main/java/com/auth0/android/jwt/ClaimImpl.java b/lib/src/main/java/com/auth0/android/jwt/ClaimImpl.java
index db088fb..c0dc64d 100644
--- a/lib/src/main/java/com/auth0/android/jwt/ClaimImpl.java
+++ b/lib/src/main/java/com/auth0/android/jwt/ClaimImpl.java
@@ -14,7 +14,6 @@
 /**
  * The ClaimImpl class implements the Claim interface.
  */
-@SuppressWarnings("WeakerAccess")
 class ClaimImpl extends BaseClaim {
 
     private final JsonElement value;
diff --git a/lib/src/main/java/com/auth0/android/jwt/DecodeException.java b/lib/src/main/java/com/auth0/android/jwt/DecodeException.java
index 7b055cf..a1182b8 100644
--- a/lib/src/main/java/com/auth0/android/jwt/DecodeException.java
+++ b/lib/src/main/java/com/auth0/android/jwt/DecodeException.java
@@ -1,5 +1,6 @@
 package com.auth0.android.jwt;
 
+@SuppressWarnings("WeakerAccess")
 public class DecodeException extends RuntimeException {
 
     DecodeException(String message) {
diff --git a/lib/src/main/java/com/auth0/android/jwt/JWT.java b/lib/src/main/java/com/auth0/android/jwt/JWT.java
index 39f1685..7c52d8b 100644
--- a/lib/src/main/java/com/auth0/android/jwt/JWT.java
+++ b/lib/src/main/java/com/auth0/android/jwt/JWT.java
@@ -3,13 +3,16 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.util.Base64;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.reflect.TypeToken;
-import java.io.UnsupportedEncodingException;
+
 import java.lang.reflect.Type;
+import java.nio.charset.Charset;
 import java.util.Date;
 import java.util.List;
 import java.util.Map;
@@ -21,7 +24,6 @@
 public class JWT implements Parcelable {
 
     private static final String TAG = JWT.class.getSimpleName();
-    private static final String ENCODING_UTF_8 = "UTF-8";
     private final String token;
 
     private Map<String, String> header;
@@ -161,8 +163,8 @@ public boolean isExpired(long leeway) {
             throw new IllegalArgumentException("The leeway must be a positive value.");
         }
         long todayTime = (long) (Math.floor(new Date().getTime() / 1000) * 1000); //truncate millis
-        Date futureToday = new Date((todayTime + leeway * 1000));
-        Date pastToday = new Date((todayTime - leeway * 1000));
+        Date futureToday = new Date(todayTime + leeway * 1000);
+        Date pastToday = new Date(todayTime - leeway * 1000);
         boolean expValid = payload.exp == null || !pastToday.after(payload.exp);
         boolean iatValid = payload.iat == null || !futureToday.before(payload.iat);
         return !expValid || !iatValid;
@@ -230,11 +232,9 @@ private String base64Decode(String string) {
         String decoded;
         try {
             byte[] bytes = Base64.decode(string, Base64.URL_SAFE | Base64.NO_WRAP | Base64.NO_PADDING);
-            decoded = new String(bytes, ENCODING_UTF_8);
+            decoded = new String(bytes, Charset.defaultCharset());
         } catch (IllegalArgumentException e) {
             throw new DecodeException("Received bytes didn't correspond to a valid Base64 encoded string.", e);
-        } catch (UnsupportedEncodingException e) {
-            throw new DecodeException("Device doesn't support UTF-8 charset encoding.", e);
         }
         return decoded;
     }
diff --git a/lib/src/main/java/com/auth0/android/jwt/JWTDeserializer.java b/lib/src/main/java/com/auth0/android/jwt/JWTDeserializer.java
index 3a379fa..2b3d339 100644
--- a/lib/src/main/java/com/auth0/android/jwt/JWTDeserializer.java
+++ b/lib/src/main/java/com/auth0/android/jwt/JWTDeserializer.java
@@ -42,6 +42,7 @@ public JWTPayload deserialize(JsonElement json, Type typeOfT, JsonDeserializatio
         return new JWTPayload(iss, sub, exp, nbf, iat, jti, aud, extra);
     }
 
+    @SuppressWarnings("SameParameterValue")
     private List<String> getStringOrArray(JsonObject obj, String claimName) {
         List<String> list = Collections.emptyList();
         if (obj.has(claimName)) {
diff --git a/lib/src/test/java/com/auth0/android/jwt/BaseClaimTest.java b/lib/src/test/java/com/auth0/android/jwt/BaseClaimTest.java
index 90b9465..41eaf67 100644
--- a/lib/src/test/java/com/auth0/android/jwt/BaseClaimTest.java
+++ b/lib/src/test/java/com/auth0/android/jwt/BaseClaimTest.java
@@ -5,64 +5,64 @@
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.collection.IsArrayWithSize.emptyArray;
 import static org.hamcrest.collection.IsEmptyCollection.empty;
 import static org.hamcrest.core.IsNull.nullValue;
-import static org.junit.Assert.assertThat;
 
 public class BaseClaimTest {
 
     private BaseClaim claim;
 
     @Before
-    public void setUp() throws Exception {
+    public void setUp() {
         claim = new BaseClaim();
     }
 
     @Test
-    public void shouldGetAsBoolean() throws Exception {
+    public void shouldGetAsBoolean() {
         assertThat(claim.asBoolean(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetAsInt() throws Exception {
+    public void shouldGetAsInt() {
         assertThat(claim.asInt(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetAsLong() throws Exception {
+    public void shouldGetAsLong() {
         assertThat(claim.asLong(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetAsDouble() throws Exception {
+    public void shouldGetAsDouble() {
         assertThat(claim.asDouble(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetAsString() throws Exception {
+    public void shouldGetAsString() {
         assertThat(claim.asString(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetAsDate() throws Exception {
+    public void shouldGetAsDate() {
         assertThat(claim.asDate(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetAsArray() throws Exception {
+    public void shouldGetAsArray() {
         assertThat(claim.asArray(Object.class), is(notNullValue()));
         assertThat(claim.asArray(Object.class), is(emptyArray()));
     }
 
     @Test
-    public void shouldGetAsList() throws Exception {
+    public void shouldGetAsList() {
         assertThat(claim.asList(Object.class), is(notNullValue()));
         assertThat(claim.asList(Object.class), is(empty()));
     }
 
     @Test
-    public void shouldGetAsObject() throws Exception {
+    public void shouldGetAsObject() {
         assertThat(claim.asObject(Object.class), is(nullValue()));
     }
 }
\ No newline at end of file
diff --git a/lib/src/test/java/com/auth0/android/jwt/ClaimImplTest.java b/lib/src/test/java/com/auth0/android/jwt/ClaimImplTest.java
index d4730cc..4f1d61d 100644
--- a/lib/src/test/java/com/auth0/android/jwt/ClaimImplTest.java
+++ b/lib/src/test/java/com/auth0/android/jwt/ClaimImplTest.java
@@ -1,17 +1,8 @@
 package com.auth0.android.jwt;
 
-import static org.hamcrest.CoreMatchers.is;
-import static org.hamcrest.CoreMatchers.notNullValue;
-import static org.hamcrest.CoreMatchers.nullValue;
-import static org.hamcrest.collection.IsArrayContainingInOrder.arrayContaining;
-import static org.hamcrest.core.IsCollectionContaining.hasItems;
-import static org.junit.Assert.assertThat;
-import static org.mockito.MockitoAnnotations.initMocks;
-
 import com.google.gson.Gson;
 import com.google.gson.JsonElement;
-import java.util.Arrays;
-import java.util.Date;
+
 import org.hamcrest.collection.IsArrayWithSize;
 import org.hamcrest.collection.IsEmptyCollection;
 import org.junit.Before;
@@ -22,22 +13,33 @@
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
+import java.util.Arrays;
+import java.util.Date;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.collection.IsArrayContainingInOrder.arrayContaining;
+import static org.hamcrest.core.IsCollectionContaining.hasItems;
+import static org.mockito.MockitoAnnotations.initMocks;
+
 @RunWith(RobolectricTestRunner.class)
 @Config(sdk = 23)
 public class ClaimImplTest {
 
-    Gson gson;
+    private Gson gson;
     @Rule
     public ExpectedException exception = ExpectedException.none();
 
     @Before
-    public void setUp() throws Exception {
+    public void setUp() {
         initMocks(this);
         gson = new Gson();
     }
 
     @Test
-    public void shouldGetBooleanValue() throws Exception {
+    public void shouldGetBooleanValue() {
         JsonElement value = gson.toJsonTree(true);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -46,7 +48,7 @@ public void shouldGetBooleanValue() throws Exception {
     }
 
     @Test
-    public void shouldGetNullBooleanIfNotPrimitiveValue() throws Exception {
+    public void shouldGetNullBooleanIfNotPrimitiveValue() {
         JsonElement value = gson.toJsonTree(new Object());
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -54,7 +56,7 @@ public void shouldGetNullBooleanIfNotPrimitiveValue() throws Exception {
     }
 
     @Test
-    public void shouldGetIntValue() throws Exception {
+    public void shouldGetIntValue() {
         JsonElement value = gson.toJsonTree(123);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -63,7 +65,7 @@ public void shouldGetIntValue() throws Exception {
     }
 
     @Test
-    public void shouldGetLongValue() throws Exception {
+    public void shouldGetLongValue() {
         JsonElement value = gson.toJsonTree(123L);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -72,7 +74,7 @@ public void shouldGetLongValue() throws Exception {
     }
 
     @Test
-    public void shouldGetNullIntIfNotPrimitiveValue() throws Exception {
+    public void shouldGetNullIntIfNotPrimitiveValue() {
         JsonElement value = gson.toJsonTree(new Object());
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -80,7 +82,7 @@ public void shouldGetNullIntIfNotPrimitiveValue() throws Exception {
     }
 
     @Test
-    public void shouldGetNullLongIfNotPrimitiveValue() throws Exception {
+    public void shouldGetNullLongIfNotPrimitiveValue() {
         JsonElement value = gson.toJsonTree(new Object());
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -88,7 +90,7 @@ public void shouldGetNullLongIfNotPrimitiveValue() throws Exception {
     }
 
     @Test
-    public void shouldGetDoubleValue() throws Exception {
+    public void shouldGetDoubleValue() {
         JsonElement value = gson.toJsonTree(1.5);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -97,7 +99,7 @@ public void shouldGetDoubleValue() throws Exception {
     }
 
     @Test
-    public void shouldGetNullDoubleIfNotPrimitiveValue() throws Exception {
+    public void shouldGetNullDoubleIfNotPrimitiveValue() {
         JsonElement value = gson.toJsonTree(new Object());
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -105,7 +107,7 @@ public void shouldGetNullDoubleIfNotPrimitiveValue() throws Exception {
     }
 
     @Test
-    public void shouldGetLargeDateValue() throws Exception {
+    public void shouldGetLargeDateValue() {
         long seconds = Integer.MAX_VALUE + 10000L;
         JsonElement value = gson.toJsonTree(seconds);
         ClaimImpl claim = new ClaimImpl(value);
@@ -117,7 +119,7 @@ public void shouldGetLargeDateValue() throws Exception {
     }
 
     @Test
-    public void shouldGetDateValue() throws Exception {
+    public void shouldGetDateValue() {
         JsonElement value = gson.toJsonTree("1476824844");
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -126,7 +128,7 @@ public void shouldGetDateValue() throws Exception {
     }
 
     @Test
-    public void shouldGetNullDateIfNotPrimitiveValue() throws Exception {
+    public void shouldGetNullDateIfNotPrimitiveValue() {
         JsonElement value = gson.toJsonTree(new Object());
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -134,7 +136,7 @@ public void shouldGetNullDateIfNotPrimitiveValue() throws Exception {
     }
 
     @Test
-    public void shouldGetStringValue() throws Exception {
+    public void shouldGetStringValue() {
         JsonElement value = gson.toJsonTree("string");
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -143,7 +145,7 @@ public void shouldGetStringValue() throws Exception {
     }
 
     @Test
-    public void shouldGetNullStringIfNotPrimitiveValue() throws Exception {
+    public void shouldGetNullStringIfNotPrimitiveValue() {
         JsonElement value = gson.toJsonTree(new Object());
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -151,7 +153,7 @@ public void shouldGetNullStringIfNotPrimitiveValue() throws Exception {
     }
 
     @Test
-    public void shouldGetArrayValueOfCustomClass() throws Exception {
+    public void shouldGetArrayValueOfCustomClass() {
         JsonElement value = gson.toJsonTree(new UserPojo[]{new UserPojo("George", 1), new UserPojo("Mark", 2)});
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -160,7 +162,7 @@ public void shouldGetArrayValueOfCustomClass() throws Exception {
     }
 
     @Test
-    public void shouldGetArrayValue() throws Exception {
+    public void shouldGetArrayValue() {
         JsonElement value = gson.toJsonTree(new String[]{"string1", "string2"});
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -169,7 +171,7 @@ public void shouldGetArrayValue() throws Exception {
     }
 
     @Test
-    public void shouldGetEmptyArrayIfNullValue() throws Exception {
+    public void shouldGetEmptyArrayIfNullValue() {
         JsonElement value = gson.toJsonTree(null);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -178,7 +180,7 @@ public void shouldGetEmptyArrayIfNullValue() throws Exception {
     }
 
     @Test
-    public void shouldGetEmptyArrayIfNonArrayValue() throws Exception {
+    public void shouldGetEmptyArrayIfNonArrayValue() {
         JsonElement value = gson.toJsonTree(1);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -187,7 +189,7 @@ public void shouldGetEmptyArrayIfNonArrayValue() throws Exception {
     }
 
     @Test
-    public void shouldThrowIfArrayClassMismatch() throws Exception {
+    public void shouldThrowIfArrayClassMismatch() {
         JsonElement value = gson.toJsonTree(new String[]{"keys", "values"});
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -196,7 +198,7 @@ public void shouldThrowIfArrayClassMismatch() throws Exception {
     }
 
     @Test
-    public void shouldGetListValueOfCustomClass() throws Exception {
+    public void shouldGetListValueOfCustomClass() {
         JsonElement value = gson.toJsonTree(Arrays.asList(new UserPojo("George", 1), new UserPojo("Mark", 2)));
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -205,7 +207,7 @@ public void shouldGetListValueOfCustomClass() throws Exception {
     }
 
     @Test
-    public void shouldGetListValue() throws Exception {
+    public void shouldGetListValue() {
         JsonElement value = gson.toJsonTree(Arrays.asList("string1", "string2"));
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -214,7 +216,7 @@ public void shouldGetListValue() throws Exception {
     }
 
     @Test
-    public void shouldGetEmptyListIfNullValue() throws Exception {
+    public void shouldGetEmptyListIfNullValue() {
         JsonElement value = gson.toJsonTree(null);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -223,7 +225,7 @@ public void shouldGetEmptyListIfNullValue() throws Exception {
     }
 
     @Test
-    public void shouldGetEmptyListIfNonArrayValue() throws Exception {
+    public void shouldGetEmptyListIfNonArrayValue() {
         JsonElement value = gson.toJsonTree(1);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -232,7 +234,7 @@ public void shouldGetEmptyListIfNonArrayValue() throws Exception {
     }
 
     @Test
-    public void shouldThrowIfListClassMismatch() throws Exception {
+    public void shouldThrowIfListClassMismatch() {
         JsonElement value = gson.toJsonTree(new String[]{"keys", "values"});
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -241,7 +243,7 @@ public void shouldThrowIfListClassMismatch() throws Exception {
     }
 
     @Test
-    public void shouldGetAsObject() throws Exception {
+    public void shouldGetAsObject() {
         UserPojo data = new UserPojo("George", 1);
         JsonElement userValue = gson.toJsonTree(data);
         ClaimImpl userClaim = new ClaimImpl(userValue);
@@ -263,7 +265,7 @@ public void shouldGetAsObject() throws Exception {
     }
 
     @Test
-    public void shouldGetNullObjectIfNullValue() throws Exception {
+    public void shouldGetNullObjectIfNullValue() {
         JsonElement value = gson.toJsonTree(null);
         ClaimImpl claim = new ClaimImpl(value);
 
@@ -271,7 +273,7 @@ public void shouldGetNullObjectIfNullValue() throws Exception {
     }
 
     @Test
-    public void shouldThrowIfObjectClassMismatch() throws Exception {
+    public void shouldThrowIfObjectClassMismatch() {
         JsonElement value = gson.toJsonTree(1);
         ClaimImpl claim = new ClaimImpl(value);
 
diff --git a/lib/src/test/java/com/auth0/android/jwt/JWTTest.java b/lib/src/test/java/com/auth0/android/jwt/JWTTest.java
index 69aec78..14318c7 100644
--- a/lib/src/test/java/com/auth0/android/jwt/JWTTest.java
+++ b/lib/src/test/java/com/auth0/android/jwt/JWTTest.java
@@ -1,26 +1,12 @@
 package com.auth0.android.jwt;
 
-import static org.hamcrest.CoreMatchers.equalTo;
-import static org.hamcrest.CoreMatchers.not;
-import static org.hamcrest.CoreMatchers.notNullValue;
-import static org.hamcrest.CoreMatchers.nullValue;
-import static org.hamcrest.MatcherAssert.assertThat;
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.collection.IsCollectionWithSize.hasSize;
-import static org.hamcrest.collection.IsMapContaining.hasEntry;
-import static org.hamcrest.core.IsCollectionContaining.hasItems;
-import static org.hamcrest.core.IsInstanceOf.instanceOf;
-
 import android.os.Bundle;
 import android.os.Parcel;
 import android.support.annotation.Nullable;
 import android.util.Base64;
-import java.nio.charset.StandardCharsets;
-import java.util.Date;
-import java.util.Map;
+
 import org.hamcrest.collection.IsEmptyCollection;
 import org.hamcrest.core.IsCollectionContaining;
-import org.junit.Assert;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -28,39 +14,52 @@
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
+import java.nio.charset.Charset;
+import java.util.Date;
+import java.util.Map;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.collection.IsCollectionWithSize.hasSize;
+import static org.hamcrest.collection.IsMapContaining.hasEntry;
+import static org.hamcrest.core.IsCollectionContaining.hasItems;
+import static org.hamcrest.core.IsInstanceOf.instanceOf;
+
 @RunWith(RobolectricTestRunner.class)
 @Config(sdk = 23)
 public class JWTTest {
 
-    private static final String CHARSET_UTF_8 = "UTF-8";
-
     @Rule
     public ExpectedException exception = ExpectedException.none();
 
     // Exceptions
     @Test
-    public void shouldThrowIfLessThan3Parts() throws Exception {
+    public void shouldThrowIfLessThan3Parts() {
         exception.expect(DecodeException.class);
         exception.expectMessage("The token was expected to have 3 parts, but got 2.");
         new JWT("two.parts");
     }
 
     @Test
-    public void shouldThrowIfMoreThan3Parts() throws Exception {
+    public void shouldThrowIfMoreThan3Parts() {
         exception.expect(DecodeException.class);
         exception.expectMessage("The token was expected to have 3 parts, but got 4.");
         new JWT("this.has.four.parts");
     }
 
     @Test
-    public void shouldThrowIfItsNotBase64Encoded() throws Exception {
+    public void shouldThrowIfItsNotBase64Encoded() {
         exception.expect(DecodeException.class);
         exception.expectMessage("Received bytes didn't correspond to a valid Base64 encoded string.");
         new JWT("thisIsNot.Base64_Enc.oded");
     }
 
     @Test
-    public void shouldThrowIfPayloadHasInvalidJSONFormat() throws Exception {
+    public void shouldThrowIfPayloadHasInvalidJSONFormat() {
         exception.expect(DecodeException.class);
         exception.expectMessage("The token's payload had an invalid JSON format.");
         new JWT("eyJhbGciOiJIUzI1NiJ9.e30ijfe923.XmNK3GpH3Ys_7lyQ");
@@ -68,7 +67,7 @@ public void shouldThrowIfPayloadHasInvalidJSONFormat() throws Exception {
 
     // toString
     @Test
-    public void shouldGetStringToken() throws Exception {
+    public void shouldGetStringToken() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.XmNK3GpH3Ys_7wsYBfq4C3M6goz71I7dTgUkuIa5lyQ");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.toString(), is(notNullValue()));
@@ -78,7 +77,7 @@ public void shouldGetStringToken() throws Exception {
     // Parts
 
     @Test
-    public void shouldGetHeader() throws Exception {
+    public void shouldGetHeader() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.XmNK3GpH3Ys_7wsYBfq4C3M6goz71I7dTgUkuIa5lyQ");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getHeader(), is(instanceOf(Map.class)));
@@ -86,14 +85,14 @@ public void shouldGetHeader() throws Exception {
     }
 
     @Test
-    public void shouldGetSignature() throws Exception {
+    public void shouldGetSignature() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.XmNK3GpH3Ys_7wsYBfq4C3M6goz71I7dTgUkuIa5lyQ");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getSignature(), is("XmNK3GpH3Ys_7wsYBfq4C3M6goz71I7dTgUkuIa5lyQ"));
     }
 
     @Test
-    public void shouldGetEmptySignature() throws Exception {
+    public void shouldGetEmptySignature() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getSignature(), is(""));
@@ -102,37 +101,37 @@ public void shouldGetEmptySignature() throws Exception {
     // Public Claims
 
     @Test
-    public void shouldGetIssuer() throws Exception {
+    public void shouldGetIssuer() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJKb2huIERvZSJ9.SgXosfRR_IwCgHq5lF3tlM-JHtpucWCRSaVuoHTbWbQ");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getIssuer(), is("John Doe"));
     }
 
     @Test
-    public void shouldGetNullIssuerIfMissing() throws Exception {
+    public void shouldGetNullIssuerIfMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.something");
         assertThat(jwt, is(notNullValue()));
 
-        Assert.assertThat(jwt.getIssuer(), is(nullValue()));
+        assertThat(jwt.getIssuer(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetSubject() throws Exception {
+    public void shouldGetSubject() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJUb2szbnMifQ.RudAxkslimoOY3BLl2Ghny3BrUKu9I1ZrXzCZGDJtNs");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getSubject(), is("Tok3ns"));
     }
 
     @Test
-    public void shouldGetNullSubjectIfMissing() throws Exception {
+    public void shouldGetNullSubjectIfMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.something");
         assertThat(jwt, is(notNullValue()));
 
-        Assert.assertThat(jwt.getSubject(), is(nullValue()));
+        assertThat(jwt.getSubject(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetArrayAudience() throws Exception {
+    public void shouldGetArrayAudience() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJhdWQiOlsiSG9wZSIsIlRyYXZpcyIsIlNvbG9tb24iXX0.Tm4W8WnfPjlmHSmKFakdij0on2rWPETpoM7Sh0u6-S4");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getAudience(), is(hasSize(3)));
@@ -140,7 +139,7 @@ public void shouldGetArrayAudience() throws Exception {
     }
 
     @Test
-    public void shouldGetStringAudience() throws Exception {
+    public void shouldGetStringAudience() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJKYWNrIFJleWVzIn0.a4I9BBhPt1OB1GW67g2P1bEHgi6zgOjGUL4LvhE9Dgc");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getAudience(), is(hasSize(1)));
@@ -148,15 +147,15 @@ public void shouldGetStringAudience() throws Exception {
     }
 
     @Test
-    public void shouldGetEmptyListAudienceIfMissing() throws Exception {
+    public void shouldGetEmptyListAudienceIfMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.something");
         assertThat(jwt, is(notNullValue()));
 
-        Assert.assertThat(jwt.getAudience(), IsEmptyCollection.<String>empty());
+        assertThat(jwt.getAudience(), IsEmptyCollection.<String>empty());
     }
 
     @Test
-    public void shouldDeserializeDatesUsingLong() throws Exception {
+    public void shouldDeserializeDatesUsingLong() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOjIxNDc0OTM2NDcsIm5iZiI6MjE0NzQ5MzY0NywiZXhwIjoyMTQ3NDkzNjQ3LCJjdG0iOjIxNDc0OTM2NDd9.txmUJ0UCy2pqTFrEgj49eNDQCWUSW_XRMjMaRqcrgLg");
         assertThat(jwt, is(notNullValue()));
 
@@ -169,7 +168,7 @@ public void shouldDeserializeDatesUsingLong() throws Exception {
     }
 
     @Test
-    public void shouldGetExpirationTime() throws Exception {
+    public void shouldGetExpirationTime() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJleHAiOiIxNDc2NzI3MDg2In0.XwZztHlQwnAgmnQvrcWXJloLOUaLZGiY0HOXJCKRaks");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getExpiresAt(), is(instanceOf(Date.class)));
@@ -180,15 +179,15 @@ public void shouldGetExpirationTime() throws Exception {
     }
 
     @Test
-    public void shouldGetNullExpirationTimeIfMissing() throws Exception {
+    public void shouldGetNullExpirationTimeIfMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.something");
         assertThat(jwt, is(notNullValue()));
 
-        Assert.assertThat(jwt.getExpiresAt(), is(nullValue()));
+        assertThat(jwt.getExpiresAt(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetNotBefore() throws Exception {
+    public void shouldGetNotBefore() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJuYmYiOiIxNDc2NzI3MDg2In0.pi3Fi3oFiXk5A5AetDdL0hjVx_rt6F5r_YiG6HoCYDw");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getNotBefore(), is(instanceOf(Date.class)));
@@ -199,15 +198,15 @@ public void shouldGetNotBefore() throws Exception {
     }
 
     @Test
-    public void shouldGetNullNotBeforeIfMissing() throws Exception {
+    public void shouldGetNullNotBeforeIfMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.something");
         assertThat(jwt, is(notNullValue()));
 
-        Assert.assertThat(jwt.getNotBefore(), is(nullValue()));
+        assertThat(jwt.getNotBefore(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetIssuedAt() throws Exception {
+    public void shouldGetIssuedAt() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJpYXQiOiIxNDc2NzI3MDg2In0.u6BxwrO7S0sqDY8-1cUOLzU2uejAJBzQQF8g_o5BAgo");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getIssuedAt(), is(instanceOf(Date.class)));
@@ -218,104 +217,105 @@ public void shouldGetIssuedAt() throws Exception {
     }
 
     @Test
-    public void shouldGetNullIssuedAtIfMissing() throws Exception {
+    public void shouldGetNullIssuedAtIfMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.something");
         assertThat(jwt, is(notNullValue()));
 
-        Assert.assertThat(jwt.getIssuedAt(), is(nullValue()));
+        assertThat(jwt.getIssuedAt(), is(nullValue()));
     }
 
     @Test
-    public void shouldGetId() throws Exception {
+    public void shouldGetId() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJqdGkiOiIxMjM0NTY3ODkwIn0.m3zgEfVUFOd-CvL3xG5BuOWLzb0zMQZCqiVNQQOPOvA");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getId(), is("1234567890"));
     }
 
     @Test
-    public void shouldGetNullIdIfMissing() throws Exception {
+    public void shouldGetNullIdIfMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.something");
         assertThat(jwt, is(notNullValue()));
 
-        Assert.assertThat(jwt.getId(), is(nullValue()));
+        assertThat(jwt.getId(), is(nullValue()));
     }
 
     @Test
-    public void shouldNotBeDeemedExpiredWithoutDateClaims() throws Exception {
+    public void shouldNotBeDeemedExpiredWithoutDateClaims() {
         JWT jwt = customTimeJWT(null, null);
         assertThat(jwt.isExpired(0), is(false));
     }
 
     @Test
-    public void shouldNotBeDeemedExpired() throws Exception {
+    public void shouldNotBeDeemedExpired() {
         JWT jwt = customTimeJWT(null, new Date().getTime() + 2000);
         assertThat(jwt.isExpired(0), is(false));
     }
 
     @Test
-    public void shouldBeDeemedExpired() throws Exception {
+    public void shouldBeDeemedExpired() {
         JWT jwt = customTimeJWT(null, new Date().getTime() - 2000);
         assertThat(jwt.isExpired(0), is(true));
     }
 
     @Test
-    public void shouldNotBeDeemedExpiredByLeeway() throws Exception {
+    public void shouldNotBeDeemedExpiredByLeeway() {
         JWT jwt = customTimeJWT(null, new Date().getTime() - 1000);
         assertThat(jwt.isExpired(2), is(false));
     }
 
     @Test
-    public void shouldBeDeemedExpiredByLeeway() throws Exception {
+    public void shouldBeDeemedExpiredByLeeway() {
         JWT jwt = customTimeJWT(null, new Date().getTime() - 2000);
         assertThat(jwt.isExpired(1), is(true));
     }
 
     @Test
-    public void shouldNotBeDeemedFutureIssued() throws Exception {
+    public void shouldNotBeDeemedFutureIssued() {
         JWT jwt = customTimeJWT(new Date().getTime() - 2000, null);
         assertThat(jwt.isExpired(0), is(false));
     }
 
     @Test
-    public void shouldBeDeemedFutureIssued() throws Exception {
+    public void shouldBeDeemedFutureIssued() {
         JWT jwt = customTimeJWT(new Date().getTime() + 2000, null);
         assertThat(jwt.isExpired(0), is(true));
     }
 
     @Test
-    public void shouldNotBeDeemedFutureIssuedByLeeway() throws Exception {
+    public void shouldNotBeDeemedFutureIssuedByLeeway() {
         JWT jwt = customTimeJWT(new Date().getTime() + 1000, null);
         assertThat(jwt.isExpired(2), is(false));
     }
 
     @Test
-    public void shouldBeDeemedFutureIssuedByLeeway() throws Exception {
+    public void shouldBeDeemedFutureIssuedByLeeway() {
         JWT jwt = customTimeJWT(new Date().getTime() + 2000, null);
         assertThat(jwt.isExpired(1), is(true));
     }
 
     @Test
-    public void shouldBeDeemedNotTimeValid() throws Exception {
+    public void shouldBeDeemedNotTimeValid() {
         JWT jwt = customTimeJWT(new Date().getTime() + 1000, new Date().getTime() - 1000);
         assertThat(jwt.isExpired(0), is(true));
     }
 
     @Test
-    public void shouldBeDeemedTimeValid() throws Exception {
+    public void shouldBeDeemedTimeValid() {
         JWT jwt = customTimeJWT(new Date().getTime() - 1000, new Date().getTime() + 1000);
         assertThat(jwt.isExpired(0), is(false));
     }
 
     @Test
-    public void shouldThrowIfLeewayIsNegative() throws Exception {
+    public void shouldThrowIfLeewayIsNegative() {
         exception.expect(IllegalArgumentException.class);
         exception.expectMessage("The leeway must be a positive value.");
         JWT jwt = customTimeJWT(null, null);
         jwt.isExpired(-1);
     }
 
+    @SuppressWarnings("ConstantConditions")
     @Test
-    public void shouldNotRemoveKnownPublicClaimsFromTree() throws Exception {
+    public void shouldNotRemoveKnownPublicClaimsFromTree() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJhdXRoMCIsInN1YiI6ImVtYWlscyIsImF1ZCI6InVzZXJzIiwiaWF0IjoxMDEwMTAxMCwiZXhwIjoxMTExMTExMSwibmJmIjoxMDEwMTAxMSwianRpIjoiaWRpZCIsInJvbGVzIjoiYWRtaW4ifQ.jCchxb-mdMTq5EpeVMSQyTp6zSwByKnfl9U-Zc9kg_w");
 
         assertThat(jwt, is(notNullValue()));
@@ -341,7 +341,7 @@ public void shouldNotRemoveKnownPublicClaimsFromTree() throws Exception {
     //Private Claims
 
     @Test
-    public void shouldGetBaseClaimIfClaimIsMissing() throws Exception {
+    public void shouldGetBaseClaimIfClaimIsMissing() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.K17vlwhE8FCMShdl1_65jEYqsQqBOVMPUU9IgG-QlTM");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getClaim("notExisting"), is(notNullValue()));
@@ -350,7 +350,7 @@ public void shouldGetBaseClaimIfClaimIsMissing() throws Exception {
     }
 
     @Test
-    public void shouldGetClaim() throws Exception {
+    public void shouldGetClaim() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJvYmplY3QiOnsibmFtZSI6ImpvaG4ifX0.lrU1gZlOdlmTTeZwq0VI-pZx2iV46UWYd5-lCjy6-c4");
         assertThat(jwt, is(notNullValue()));
         assertThat(jwt.getClaim("object"), is(notNullValue()));
@@ -358,7 +358,7 @@ public void shouldGetClaim() throws Exception {
     }
 
     @Test
-    public void shouldGetAllClaims() throws Exception {
+    public void shouldGetAllClaims() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.eyJvYmplY3QiOnsibmFtZSI6ImpvaG4ifSwic3ViIjoiYXV0aDAifQ.U20MgOAV81c54mRelwYDJiLllb5OVwUAtMGn-eUOpTA");
         assertThat(jwt, is(notNullValue()));
         Map<String, Claim> claims = jwt.getClaims();
@@ -372,7 +372,7 @@ public void shouldGetAllClaims() throws Exception {
     }
 
     @Test
-    public void shouldGetEmptyAllClaims() throws Exception {
+    public void shouldGetEmptyAllClaims() {
         JWT jwt = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.ZRrHA1JJJW8opsbCGfG_HACGpVUMN_a9IV7pAx_Zmeo");
         assertThat(jwt, is(notNullValue()));
         Map<String, Claim> claims = jwt.getClaims();
@@ -382,8 +382,9 @@ public void shouldGetEmptyAllClaims() throws Exception {
 
     //Parcelable
 
+    @SuppressWarnings("ConstantConditions")
     @Test
-    public void shouldBeParceled() throws Exception {
+    public void shouldBeParceled() {
         JWT jwtOrigin = new JWT("eyJhbGciOiJIUzI1NiJ9.e30.K17vlwhE8FCMShdl1_65jEYqsQqBOVMPUU9IgG-QlTM");
         assertThat(jwtOrigin, is(notNullValue()));
 
@@ -435,9 +436,7 @@ private JWT customTimeJWT(@Nullable Long iatMs, @Nullable Long expMs) {
 
     private String encodeString(String source) {
         byte[] bytes = Base64.encode(source.getBytes(), Base64.URL_SAFE | Base64.NO_WRAP | Base64.NO_PADDING);
-        String res = "";
-        res = new String(bytes, StandardCharsets.UTF_8);
-        return res;
+        return new String(bytes, Charset.defaultCharset());
     }
 
 }
diff --git a/lib/src/test/java/com/auth0/android/jwt/UserPojo.java b/lib/src/test/java/com/auth0/android/jwt/UserPojo.java
index 9812cf8..31fe500 100644
--- a/lib/src/test/java/com/auth0/android/jwt/UserPojo.java
+++ b/lib/src/test/java/com/auth0/android/jwt/UserPojo.java
@@ -1,10 +1,12 @@
 package com.auth0.android.jwt;
 
-public class UserPojo {
-    String name;
-    int id;
+import java.util.Objects;
 
-    public UserPojo(String name, int id) {
+class UserPojo {
+    private String name;
+    private int id;
+
+    UserPojo(String name, int id) {
         this.name = name;
         this.id = id;
     }
@@ -17,6 +19,6 @@ public boolean equals(Object o) {
         UserPojo userPojo = (UserPojo) o;
 
         if (id != userPojo.id) return false;
-        return name != null ? name.equals(userPojo.name) : userPojo.name == null;
+        return Objects.equals(name, userPojo.name);
     }
 }