diff --git a/api/src/main/java/io/cloudevents/extensions/ExtensionFormat.java b/api/src/main/java/io/cloudevents/extensions/ExtensionFormat.java
index d937e7c6..f2823ad6 100644
--- a/api/src/main/java/io/cloudevents/extensions/ExtensionFormat.java
+++ b/api/src/main/java/io/cloudevents/extensions/ExtensionFormat.java
@@ -42,7 +42,7 @@ public interface ExtensionFormat {
 	 */
 	Map<String, String> transport();
 	
-	public static ExtensionFormat of(final InMemoryFormat inMemory,
+	static ExtensionFormat of(final InMemoryFormat inMemory,
 			final String key, final String value) {
 		
 		final Map<String, String> transport = new HashMap<>();
@@ -62,7 +62,7 @@ public interface ExtensionFormat {
 	}
 	
 	@SafeVarargs
-	public static ExtensionFormat of(final InMemoryFormat inMemory,
+	static ExtensionFormat of(final InMemoryFormat inMemory,
 			Entry<String, String> ... transport){
 		Objects.requireNonNull(inMemory);
 		Objects.requireNonNull(transport);
@@ -89,7 +89,7 @@ public interface ExtensionFormat {
 	 * @param extensions
 	 * @return
 	 */
-	public static Map<String, String> marshal(Collection<ExtensionFormat>
+	static Map<String, String> marshal(Collection<ExtensionFormat>
 		extensions) {
 		
 		return extensions.stream()
diff --git a/api/src/main/java/io/cloudevents/format/BinaryUnmarshaller.java b/api/src/main/java/io/cloudevents/format/BinaryUnmarshaller.java
index 22fa0db2..935e0d99 100644
--- a/api/src/main/java/io/cloudevents/format/BinaryUnmarshaller.java
+++ b/api/src/main/java/io/cloudevents/format/BinaryUnmarshaller.java
@@ -19,6 +19,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 import java.util.function.Supplier;
@@ -219,10 +220,8 @@ public final class BinaryUnmarshaller {
 			A attributes = attributeUnmarshaller.unmarshal(attributesMap);
 			
 			T data = attributes.getMediaType()
-				.map((mime) -> {
-					return dataUnmarshallers.get(mime);
-				})
-				.filter((un) -> null != un)
+				.map((mime) -> dataUnmarshallers.get(mime))
+				.filter(Objects::nonNull)
 				.map(unmarshaller -> 
 						unmarshaller.unmarshal(payload, attributes))
 				.orElse(null);
diff --git a/api/src/main/java/io/cloudevents/format/StructuredMarshaller.java b/api/src/main/java/io/cloudevents/format/StructuredMarshaller.java
index 749d58c6..009b8003 100644
--- a/api/src/main/java/io/cloudevents/format/StructuredMarshaller.java
+++ b/api/src/main/java/io/cloudevents/format/StructuredMarshaller.java
@@ -51,7 +51,7 @@ public class StructuredMarshaller {
 		return new Builder<>();
 	}
 		
-	public static interface MediaTypeStep<A extends Attributes, T, P, H> {
+	public interface MediaTypeStep<A extends Attributes, T, P, H> {
 		/**
 		 * Sets the media type of CloudEvents envelope
 		 * @param headerName Example {@code Content-Type} for HTTP
@@ -60,7 +60,7 @@ public class StructuredMarshaller {
 		EnvelopeMarshallerStep<A, T, P, H> mime(String headerName, H mediaType);
 	}
 	
-	public static interface EnvelopeMarshallerStep<A extends Attributes, T, P, H> {
+	public interface EnvelopeMarshallerStep<A extends Attributes, T, P, H> {
 		/**
 		 * Sets the marshaller for the CloudEvent
 		 * @param marshaller
@@ -68,7 +68,7 @@ public class StructuredMarshaller {
 		ExtensionAccessorStep<A, T, P, H> map(EnvelopeMarshaller<A, T, P> marshaller);
 	}
 	
-	public static interface ExtensionAccessorStep<A extends Attributes, T, P, H> {
+	public interface ExtensionAccessorStep<A extends Attributes, T, P, H> {
 		/**
 		 * To skip the extension special handling
 		 */
@@ -76,11 +76,11 @@ public class StructuredMarshaller {
 		ExtensionMarshallerStep<A, T, P, H> map(ExtensionFormatAccessor<A, T> accessor);
 	}
 	
-	public static interface ExtensionMarshallerStep<A extends Attributes, T, P, H> {
+	public interface ExtensionMarshallerStep<A extends Attributes, T, P, H> {
 		HeaderMapperStep<A, T, P, H> map(ExtensionMarshaller marshaller);
 	}
 	
-	public static interface HeaderMapperStep<A extends Attributes, T, P, H> {
+	public interface HeaderMapperStep<A extends Attributes, T, P, H> {
 		EventStep<A, T, P, H> map(FormatHeaderMapper<H> mapper);
 	}
 
diff --git a/api/src/main/java/io/cloudevents/format/StructuredUnmarshaller.java b/api/src/main/java/io/cloudevents/format/StructuredUnmarshaller.java
index 65818426..e64a2301 100644
--- a/api/src/main/java/io/cloudevents/format/StructuredUnmarshaller.java
+++ b/api/src/main/java/io/cloudevents/format/StructuredUnmarshaller.java
@@ -144,18 +144,15 @@ public class StructuredUnmarshaller {
 				Optional.ofNullable(extensionMapper)
 					.map(mapper -> mapper.map(headers))
 					.orElse(new HashMap<>());
-			
-			CloudEvent<A, T> result = 
-				unmarshaller.unmarshal(payload, 
-				  () -> 
+
+			return unmarshaller.unmarshal(payload,
+				  () ->
 					extensionUnmarshallers.stream()
 					.map(unmarshaller ->
 						unmarshaller.unmarshal(extensionsMap))
 					.filter(Optional::isPresent)
 					.map(Optional::get)
 					.collect(Collectors.toList()));
-			
-			return result;
 		}
 		
 	}
diff --git a/api/src/main/java/io/cloudevents/v1/http/HeaderMapper.java b/api/src/main/java/io/cloudevents/v1/http/HeaderMapper.java
index f05397c3..faece4a5 100644
--- a/api/src/main/java/io/cloudevents/v1/http/HeaderMapper.java
+++ b/api/src/main/java/io/cloudevents/v1/http/HeaderMapper.java
@@ -58,14 +58,14 @@ public class HeaderMapper {
 					.toLowerCase(Locale.US), header.getValue()))
 			.filter(header -> !header.getKey()
 					.equals(ContextAttributes.datacontenttype.name()))
-			.map(header -> new SimpleEntry<>(HEADER_PREFIX+header.getKey(),
+			.map(header -> new SimpleEntry<>(HEADER_PREFIX + header.getKey(),
 					header.getValue()))
 			.collect(Collectors.toMap(Entry::getKey, Entry::getValue));
 		
 		result.putAll(
 			extensions.entrySet()
 				.stream()
-				.filter(extension -> null!= extension.getValue())
+				.filter(extension -> null != extension.getValue())
 				.collect(Collectors.toMap(Entry::getKey, Entry::getValue))
 		);
 		
diff --git a/api/src/test/java/io/cloudevents/format/StructuredMarshallerTest.java b/api/src/test/java/io/cloudevents/format/StructuredMarshallerTest.java
index 7d602907..45395d6e 100644
--- a/api/src/test/java/io/cloudevents/format/StructuredMarshallerTest.java
+++ b/api/src/test/java/io/cloudevents/format/StructuredMarshallerTest.java
@@ -78,10 +78,7 @@ public class StructuredMarshallerTest {
 		
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
+		.map((ce) -> null)
 		.skip()
 		.withEvent(null);
 	}
@@ -91,10 +88,7 @@ public class StructuredMarshallerTest {
 		// act
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
+		.map((ce) -> null)
 		.skip()
 		.withEvent(() -> null);
 	}
@@ -106,10 +100,7 @@ public class StructuredMarshallerTest {
 		
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
+		.map((ce) -> null)
 		.map(null);
 	}
 	
@@ -118,14 +109,8 @@ public class StructuredMarshallerTest {
 		// act		
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
-		.map((event) -> {
-			
-			return null;
-		});
+		.map((ce) -> null)
+		.map((event) -> null);
 	}
 	
 	@Test
@@ -135,14 +120,8 @@ public class StructuredMarshallerTest {
 		
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
-		.map((event) -> {
-			
-			return null;
-		})
+		.map((ce) -> null)
+		.map((event) -> null)
 		.map(null);
 	}
 	
@@ -150,18 +129,9 @@ public class StructuredMarshallerTest {
 	public void should_ok_on_extension_marshaller() {
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
-		.map((event) -> {
-			
-			return null;
-		})
-		.map((extensions) -> {
-			
-			return null;
-		});
+		.map((ce) -> null)
+		.map((event) -> null)
+		.map((extensions) -> null);
 	}
 	
 	@Test
@@ -171,18 +141,9 @@ public class StructuredMarshallerTest {
 		
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
-		.map((event) -> {
-			
-			return null;
-		})
-		.map((extensions) -> {
-			
-			return null;
-		})
+		.map((ce) -> null)
+		.map((event) -> null)
+		.map((extensions) -> null)
 		.map(null);
 	}
 	
@@ -190,18 +151,9 @@ public class StructuredMarshallerTest {
 	public void should_ok_on_header_mapper() {
 		StructuredMarshaller.<Attributes, Much, String, String>builder()
 		.mime("Content-Type", "application/cloudevents+json")
-		.map((ce) -> {
-			
-			return null;
-		})
-		.map((event) -> {
-			
-			return null;
-		})
-		.map((extensions) -> {
-			
-			return null;
-		})
+		.map((ce) -> null)
+		.map((event) -> null)
+		.map((extensions) -> null)
 		.map((attributes, extensions) -> null);
 	}
 }