diff --git a/maven-compat/src/main/java/org/apache/maven/project/interpolation/StringSearchModelInterpolator.java b/maven-compat/src/main/java/org/apache/maven/project/interpolation/StringSearchModelInterpolator.java
index 553874ce4b..8dc8784b12 100644
--- a/maven-compat/src/main/java/org/apache/maven/project/interpolation/StringSearchModelInterpolator.java
+++ b/maven-compat/src/main/java/org/apache/maven/project/interpolation/StringSearchModelInterpolator.java
@@ -164,12 +164,7 @@ public class StringSearchModelInterpolator
             }
             else if ( isQualifiedForInterpolation( cls ) )
             {
-                Field[] fields = FIELDS_BY_CLASS.get( cls );
-                if ( fields == null )
-                {
-                    fields = cls.getDeclaredFields();
-                    FIELDS_BY_CLASS.put( cls, fields );
-                }
+                Field[] fields = FIELDS_BY_CLASS.computeIfAbsent( cls, k -> cls.getDeclaredFields() );
 
                 for ( Field field : fields )
                 {
diff --git a/maven-core/src/main/java/org/apache/maven/execution/ProfileActivation.java b/maven-core/src/main/java/org/apache/maven/execution/ProfileActivation.java
index 52f5e06a91..ad00a74054 100644
--- a/maven-core/src/main/java/org/apache/maven/execution/ProfileActivation.java
+++ b/maven-core/src/main/java/org/apache/maven/execution/ProfileActivation.java
@@ -133,7 +133,7 @@ public class ProfileActivation
     {
         return this.activations.entrySet().stream()
                 .filter( e -> predicate.test( e.getValue() ) )
-                .map( e -> e.getKey() )
+                .map( Map.Entry::getKey )
                 .collect( toSet() );
     }
 
diff --git a/maven-core/src/main/java/org/apache/maven/graph/DefaultProjectDependencyGraph.java b/maven-core/src/main/java/org/apache/maven/graph/DefaultProjectDependencyGraph.java
index 1f422937b1..5216988170 100644
--- a/maven-core/src/main/java/org/apache/maven/graph/DefaultProjectDependencyGraph.java
+++ b/maven-core/src/main/java/org/apache/maven/graph/DefaultProjectDependencyGraph.java
@@ -154,7 +154,7 @@ public class DefaultProjectDependencyGraph
     private List<MavenProject> getSortedProjects( Set<String> projectIds )
     {
         return projectIds.stream()
-                .map( id -> projects.get( id ) )
+                .map( projects::get )
                 .sorted( Comparator.comparingInt( order::get ) )
                 .collect( Collectors.toList() );
     }
diff --git a/maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultBuildPomXMLFilterFactory.java b/maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultBuildPomXMLFilterFactory.java
index 906584d5a7..d22eaacf0e 100644
--- a/maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultBuildPomXMLFilterFactory.java
+++ b/maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultBuildPomXMLFilterFactory.java
@@ -58,14 +58,15 @@ public class DefaultBuildPomXMLFilterFactory extends BuildToRawPomXMLFilterFacto
     @Override
     protected Function<Path, Optional<RelativeProject>> getRelativePathMapper()
     {
-        return p -> Optional.ofNullable( context.getRawModel( p ) ).map( m -> toRelativeProject( m ) );
+        return p -> Optional.ofNullable( context.getRawModel( p ) )
+                .map( DefaultBuildPomXMLFilterFactory::toRelativeProject );
     }
 
     @Override
     protected BiFunction<String, String, String> getDependencyKeyToVersionMapper()
     {
         return ( g, a ) -> Optional.ofNullable( context.getRawModel( g, a ) )
-                            .map( m -> toVersion( m ) )
+                            .map( DefaultBuildPomXMLFilterFactory::toVersion )
                             .orElse( null );
     }
 
diff --git a/maven-model-builder/src/main/java/org/apache/maven/model/building/FileToRawModelMerger.java b/maven-model-builder/src/main/java/org/apache/maven/model/building/FileToRawModelMerger.java
index f697d771d0..47af900a9a 100644
--- a/maven-model-builder/src/main/java/org/apache/maven/model/building/FileToRawModelMerger.java
+++ b/maven-model-builder/src/main/java/org/apache/maven/model/building/FileToRawModelMerger.java
@@ -80,7 +80,7 @@ class FileToRawModelMerger extends ModelMerger
                                                            boolean sourceDominant, Map<Object, Object> context )
     {
         Iterator<Dependency> sourceIterator = source.getDependencies().iterator();
-        target.getDependencies().stream().forEach( t -> mergeDependency( t, sourceIterator.next(), sourceDominant,
+        target.getDependencies().forEach( t -> mergeDependency( t, sourceIterator.next(), sourceDominant,
                                                                          context ) );
     }
 
@@ -124,7 +124,7 @@ class FileToRawModelMerger extends ModelMerger
                                         Map<Object, Object> context )
     {
         Iterator<Profile> sourceIterator = source.getProfiles().iterator();
-        target.getProfiles().stream().forEach( t -> mergeProfile( t, sourceIterator.next(), sourceDominant,
+        target.getProfiles().forEach( t -> mergeProfile( t, sourceIterator.next(), sourceDominant,
                                                                   context ) );
     }
 
@@ -133,7 +133,7 @@ class FileToRawModelMerger extends ModelMerger
                                                 Map<Object, Object> context )
     {
         Iterator<Dependency> sourceIterator = source.getDependencies().iterator();
-        target.getDependencies().stream().forEach( t -> mergeDependency( t, sourceIterator.next(), sourceDominant,
+        target.getDependencies().forEach( t -> mergeDependency( t, sourceIterator.next(), sourceDominant,
                                                                          context ) );
     }
 
@@ -156,7 +156,7 @@ class FileToRawModelMerger extends ModelMerger
                                              Map<Object, Object> context )
     {
         Iterator<Dependency> sourceIterator = source.getDependencies().iterator();
-        target.getDependencies().stream().forEach( t -> mergeDependency( t, sourceIterator.next(), sourceDominant,
+        target.getDependencies().forEach( t -> mergeDependency( t, sourceIterator.next(), sourceDominant,
                                                                          context ) );
     }
 
diff --git a/maven-model-transform/src/main/java/org/apache/maven/model/transform/AbstractEventXMLFilter.java b/maven-model-transform/src/main/java/org/apache/maven/model/transform/AbstractEventXMLFilter.java
index 7264145605..711845f5a6 100644
--- a/maven-model-transform/src/main/java/org/apache/maven/model/transform/AbstractEventXMLFilter.java
+++ b/maven-model-transform/src/main/java/org/apache/maven/model/transform/AbstractEventXMLFilter.java
@@ -86,16 +86,14 @@ abstract class AbstractEventXMLFilter extends AbstractSAXFilter
 
             if ( !lockCharacters )
             {
-                charactersSegments.stream().forEach( e ->
-                {
-                    saxEvents.add( () ->
-                    {
-                        if ( acceptEvent( eventState ) )
+                charactersSegments.forEach( e ->
+                        saxEvents.add( () ->
                         {
-                            e.execute();
-                        }
-                    } );
-                } );
+                            if ( acceptEvent( eventState ) )
+                            {
+                                e.execute();
+                            }
+                        } ) );
                 charactersSegments.clear();
             }
 
@@ -127,16 +125,14 @@ abstract class AbstractEventXMLFilter extends AbstractSAXFilter
     protected final void executeEvents() throws SAXException
     {
         final String eventState = getState();
-        charactersSegments.stream().forEach( e ->
-        {
-            saxEvents.add( () ->
-            {
-                if ( acceptEvent( eventState ) )
+        charactersSegments.forEach( e ->
+                saxEvents.add( () ->
                 {
-                    e.execute();
-                }
-            } );
-        } );
+                    if ( acceptEvent( eventState ) )
+                    {
+                        e.execute();
+                    }
+                } ) );
         charactersSegments.clear();
 
         // not with streams due to checked SAXException
diff --git a/maven-model-transform/src/main/java/org/apache/maven/model/transform/sax/SAXEventFactory.java b/maven-model-transform/src/main/java/org/apache/maven/model/transform/sax/SAXEventFactory.java
index 8625762e24..c9ae4864cb 100644
--- a/maven-model-transform/src/main/java/org/apache/maven/model/transform/sax/SAXEventFactory.java
+++ b/maven-model-transform/src/main/java/org/apache/maven/model/transform/sax/SAXEventFactory.java
@@ -51,7 +51,7 @@ public final class SAXEventFactory
 
     public SAXEvent endDocument()
     {
-        return () -> contentHandler.endDocument();
+        return contentHandler::endDocument;
     }
 
     public SAXEvent endElement( final String uri, final String localName, final String qName )
@@ -86,7 +86,7 @@ public final class SAXEventFactory
 
     public SAXEvent startDocument()
     {
-        return () -> contentHandler.startDocument();
+        return contentHandler::startDocument;
     }
 
     public SAXEvent startElement( final String uri, final String localName, final String qName, final Attributes atts )
@@ -111,7 +111,7 @@ public final class SAXEventFactory
 
     public SAXEvent endDTD()
     {
-        return () -> lexicalHandler.endDTD();
+        return lexicalHandler::endDTD;
     }
 
     public SAXEvent startEntity( String name )
@@ -127,12 +127,12 @@ public final class SAXEventFactory
 
     public SAXEvent startCDATA()
     {
-        return () -> lexicalHandler.startCDATA();
+        return lexicalHandler::startCDATA;
     }
 
     public SAXEvent endCDATA()
     {
-        return () -> lexicalHandler.endCDATA();
+        return lexicalHandler::endCDATA;
     }
 
     public SAXEvent comment( char[] ch, int start, int length )