diff --git a/src/main/java/com/mastercard/developer/utils/StringUtils.java b/src/main/java/com/mastercard/developer/utils/StringUtils.java
index d3e5e01..59ab879 100644
--- a/src/main/java/com/mastercard/developer/utils/StringUtils.java
+++ b/src/main/java/com/mastercard/developer/utils/StringUtils.java
@@ -6,6 +6,6 @@ private StringUtils() {
     }
 
     public static boolean isNullOrEmpty(String str) {
-        return null == str || str.length() == 0;
+        return null == str || str.isEmpty();
     }
-}
\ No newline at end of file
+}
diff --git a/src/test/java/com/mastercard/developer/encryption/FieldLevelEncryptionConfigBuilderTest.java b/src/test/java/com/mastercard/developer/encryption/FieldLevelEncryptionConfigBuilderTest.java
index 13cb574..0ea5001 100644
--- a/src/test/java/com/mastercard/developer/encryption/FieldLevelEncryptionConfigBuilderTest.java
+++ b/src/test/java/com/mastercard/developer/encryption/FieldLevelEncryptionConfigBuilderTest.java
@@ -60,7 +60,7 @@ public void testBuild_Nominal_iv12() throws Exception {
         Assert.assertEquals("oaepPaddingDigestAlgorithm", config.oaepPaddingDigestAlgorithmFieldName);
         Assert.assertEquals("x-oaep-padding-digest-algorithm", config.oaepPaddingDigestAlgorithmHeaderName);
         Assert.assertEquals(HEX, config.fieldValueEncoding);
-        assertThat(config.getIVSize().intValue(),equalTo(12));
+        assertThat(config.getIVSize(),equalTo(12));
     }
 
     @Test
@@ -107,7 +107,7 @@ public void testBuild_Nominal_iv16() throws Exception {
         Assert.assertEquals("oaepPaddingDigestAlgorithm", config.oaepPaddingDigestAlgorithmFieldName);
         Assert.assertEquals("x-oaep-padding-digest-algorithm", config.oaepPaddingDigestAlgorithmHeaderName);
         Assert.assertEquals(HEX, config.fieldValueEncoding);
-        assertThat(config.getIVSize().intValue(),equalTo(16));
+        assertThat(config.getIVSize(),equalTo(16));
     }
 
     @Test
diff --git a/src/test/java/com/mastercard/developer/encryption/JweConfigBuilderTest.java b/src/test/java/com/mastercard/developer/encryption/JweConfigBuilderTest.java
index 76d7a4b..ac02937 100644
--- a/src/test/java/com/mastercard/developer/encryption/JweConfigBuilderTest.java
+++ b/src/test/java/com/mastercard/developer/encryption/JweConfigBuilderTest.java
@@ -34,7 +34,7 @@ public void testBuild_Nominal_iv12() throws Exception {
         Assert.assertEquals("encryptedPayload", config.getEncryptedValueFieldName());
         Assert.assertEquals(Collections.singletonMap("$.encryptedPayload", "$"), config.getDecryptionPaths());
         Assert.assertEquals(Collections.singletonMap("$", "$"), config.getEncryptionPaths());
-        assertThat(config.getIVSize().intValue(),equalTo(12));
+        assertThat(config.getIVSize(),equalTo(12));
     }
 
     @Test
@@ -54,7 +54,7 @@ public void testBuild_Nominal_iv16() throws Exception {
         Assert.assertEquals("encryptedPayload", config.getEncryptedValueFieldName());
         Assert.assertEquals(Collections.singletonMap("$.encryptedPayload", "$"), config.getDecryptionPaths());
         Assert.assertEquals(Collections.singletonMap("$", "$"), config.getEncryptionPaths());
-        assertThat(config.getIVSize().intValue(),equalTo(16));
+        assertThat(config.getIVSize(),equalTo(16));
     }
 
     @Test