diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/NestedTargetPropertyMappingHolder.java b/processor/src/main/java/org/mapstruct/ap/internal/model/NestedTargetPropertyMappingHolder.java
index 10b3d4736..3c8b1bec6 100644
--- a/processor/src/main/java/org/mapstruct/ap/internal/model/NestedTargetPropertyMappingHolder.java
+++ b/processor/src/main/java/org/mapstruct/ap/internal/model/NestedTargetPropertyMappingHolder.java
@@ -352,16 +352,12 @@ public class NestedTargetPropertyMappingHolder {
                 MappingReference newMapping = mapping.popTargetReference();
                 if ( newMapping != null ) {
                     // group properties on current name.
-                    if ( !mappingsKeyedByProperty.containsKey( property ) ) {
-                        mappingsKeyedByProperty.put( property, new LinkedHashSet<>() );
-                    }
-                    mappingsKeyedByProperty.get( property ).add( newMapping );
+                    mappingsKeyedByProperty.computeIfAbsent( property, propertyEntry -> new LinkedHashSet<>() )
+                        .add( newMapping );
                 }
                 else {
-                    if ( !singleTargetReferences.containsKey( property ) ) {
-                        singleTargetReferences.put( property, new LinkedHashSet<>() );
-                    }
-                    singleTargetReferences.get( property ).add( mapping );
+                    singleTargetReferences.computeIfAbsent( property, propertyEntry -> new LinkedHashSet<>() )
+                        .add( mapping );
                 }
             }
 
@@ -459,10 +455,8 @@ public class NestedTargetPropertyMappingHolder {
             for ( MappingReference mapping : mappings ) {
                 if ( mapping.getSourceReference() != null && mapping.getSourceReference().isValid() ) {
                     Parameter parameter = mapping.getSourceReference().getParameter();
-                    if ( !mappingsKeyedByParameter.containsKey( parameter ) ) {
-                        mappingsKeyedByParameter.put( parameter, new LinkedHashSet<>() );
-                    }
-                    mappingsKeyedByParameter.get( parameter ).add( mapping );
+                    mappingsKeyedByParameter.computeIfAbsent( parameter, key -> new LinkedHashSet<>() )
+                        .add( mapping );
                 }
                 else {
                     appliesToAll.add( mapping );
@@ -530,10 +524,8 @@ public class NestedTargetPropertyMappingHolder {
                 if ( newMapping != null ) {
                     // group properties on current name.
                     PropertyEntry property = first( mapping.getSourceReference().getPropertyEntries() );
-                    if ( !mappingsKeyedByProperty.containsKey( property ) ) {
-                        mappingsKeyedByProperty.put( property, new LinkedHashSet<>() );
-                    }
-                    mappingsKeyedByProperty.get( property ).add( newMapping );
+                    mappingsKeyedByProperty.computeIfAbsent( property, propertyEntry -> new LinkedHashSet<>() )
+                        .add( newMapping );
                 }
                 //This is an ignore, or some expression, or a default. We apply these to all
                 else if ( mapping.getSourceReference() == null ) {
@@ -666,8 +658,8 @@ public class NestedTargetPropertyMappingHolder {
                 for ( MappingReference mapping : singleTargetReferences ) {
                     if ( mapping.getSourceReference() != null && mapping.getSourceReference().isValid() ) {
                         K key = keyExtractor.apply( mapping.getSourceReference() );
-                        if ( key != null && !map.containsKey( key ) ) {
-                            map.put( key, new LinkedHashSet<>() );
+                        if ( key != null ) {
+                            map.computeIfAbsent( key, keyValue -> new LinkedHashSet<>() );
                         }
                     }
                 }
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/common/Type.java b/processor/src/main/java/org/mapstruct/ap/internal/model/common/Type.java
index da2bfc76f..0a448c88a 100644
--- a/processor/src/main/java/org/mapstruct/ap/internal/model/common/Type.java
+++ b/processor/src/main/java/org/mapstruct/ap/internal/model/common/Type.java
@@ -485,23 +485,21 @@ public class Type extends ModelElement implements Comparable<Type> {
                     // In the DefaultAccessorNamingStrategy, this can only be the case for Booleans: isFoo() and
                     // getFoo(); The latter is preferred.
                     if ( !getter.getSimpleName().toString().startsWith( "is" ) ) {
-                        modifiableGetters.put( getPropertyName( getter ), getter );
+                        modifiableGetters.put( propertyName, getter );
                     }
 
                 }
                 else {
-                    modifiableGetters.put( getPropertyName( getter ), getter );
+                    modifiableGetters.put( propertyName, getter );
                 }
             }
 
             List<Accessor> fieldsList = filters.fieldsIn( getAllFields() );
             for ( Accessor field : fieldsList ) {
                 String propertyName = getPropertyName( field );
-                if ( !modifiableGetters.containsKey( propertyName ) ) {
-                    // If there was no getter or is method for booleans, then resort to the field.
-                    // If a field was already added do not add it again.
-                    modifiableGetters.put( propertyName,  field );
-                }
+                // If there was no getter or is method for booleans, then resort to the field.
+                // If a field was already added do not add it again.
+                modifiableGetters.putIfAbsent( propertyName, field );
             }
             readAccessors = Collections.unmodifiableMap( modifiableGetters );
         }