diff --git a/transpiler/src/main/java/org/jsweet/transpiler/JSweetContext.java b/transpiler/src/main/java/org/jsweet/transpiler/JSweetContext.java
index 06ce2831..01f18557 100644
--- a/transpiler/src/main/java/org/jsweet/transpiler/JSweetContext.java
+++ b/transpiler/src/main/java/org/jsweet/transpiler/JSweetContext.java
@@ -987,10 +987,14 @@ public class JSweetContext extends Context {
 	 * Gets the first value of the 'value' property for the given annotation
 	 * type if found on the given symbol.
 	 */
-	public String getAnnotationValue(Symbol symbol, String annotationType, String defaultValue) {
+	public final String getAnnotationValue(Symbol symbol, String annotationType, String defaultValue) {
 		return getAnnotationValue(symbol, annotationType, null, defaultValue);
 	}
 
+	/**
+	 * Gets the first value of the given property for the given annotation type
+	 * if found on the given symbol.
+	 */
 	public String getAnnotationValue(Symbol symbol, String annotationType, String propertyName, String defaultValue) {
 		if (hasAnnotationFilters()) {
 			String signature = symbol.toString();
diff --git a/transpiler/src/main/java/org/jsweet/transpiler/extensions/RemoveJavaDependenciesAdapter.java b/transpiler/src/main/java/org/jsweet/transpiler/extensions/RemoveJavaDependenciesAdapter.java
index 87a3e066..e56395a1 100644
--- a/transpiler/src/main/java/org/jsweet/transpiler/extensions/RemoveJavaDependenciesAdapter.java
+++ b/transpiler/src/main/java/org/jsweet/transpiler/extensions/RemoveJavaDependenciesAdapter.java
@@ -95,14 +95,14 @@ public class RemoveJavaDependenciesAdapter<C extends JSweetContext> extends Java
 		extTypesMapping.put(Calendar.class.getName(), "Date");
 		extTypesMapping.put(GregorianCalendar.class.getName(), "Date");
 		extTypesMapping.put(TimeZone.class.getName(), "string");
-		typesMapping.putAll(extTypesMapping);
-		complexTypesMapping
-				.add((typeTree,
+		addTypeMappings(extTypesMapping);
+		addTypeMapping(
+				(typeTree,
 						name) -> name.startsWith("java.")
 								&& context.types.isSubtype(typeTree.type, context.symtab.throwableType) ? "Error"
 										: null);
-		complexTypesMapping
-				.add((typeTree,
+		addTypeMapping(
+				(typeTree,
 						name) -> typeTree instanceof JCTypeApply && WeakReference.class.getName()
 								.equals(typeTree.type.tsym.getQualifiedName().toString())
 										? ((JCTypeApply) typeTree).arguments.head : null);
@@ -541,8 +541,8 @@ public class RemoveJavaDependenciesAdapter<C extends JSweetContext> extends Java
 
 	@Override
 	protected boolean substituteFieldAccess(JCFieldAccess fieldAccess, TypeSymbol targetType, String accessedType) {
-		if (fieldAccess.sym.isStatic() && typesMapping.containsKey(accessedType)
-				&& accessedType.startsWith("java.lang.") && !"class".equals(fieldAccess.name.toString())) {
+		if (fieldAccess.sym.isStatic() && isMappedType(accessedType) && accessedType.startsWith("java.lang.")
+				&& !"class".equals(fieldAccess.name.toString())) {
 
 			switch (accessedType) {
 			case "java.lang.Float":
diff --git a/transpiler/src/main/java/org/jsweet/transpiler/typescript/Java2TypeScriptAdapter.java b/transpiler/src/main/java/org/jsweet/transpiler/typescript/Java2TypeScriptAdapter.java
index f31d5ffa..b1c5e0cb 100644
--- a/transpiler/src/main/java/org/jsweet/transpiler/typescript/Java2TypeScriptAdapter.java
+++ b/transpiler/src/main/java/org/jsweet/transpiler/typescript/Java2TypeScriptAdapter.java
@@ -125,8 +125,8 @@ public class Java2TypeScriptAdapter<C extends JSweetContext> extends AbstractPri
 
 	private final static String VAR_DECL_KEYWORD = Java2TypeScriptTranslator.VAR_DECL_KEYWORD;
 
-	protected Map<String, String> typesMapping = new HashMap<String, String>();
-	protected List<BiFunction<JCTree, String, Object>> complexTypesMapping = new ArrayList<>();
+	private Map<String, String> typesMapping = new HashMap<String, String>();
+	private List<BiFunction<JCTree, String, Object>> complexTypesMapping = new ArrayList<>();
 	protected Map<String, String> langTypesMapping = new HashMap<String, String>();
 	protected Set<String> langTypesSimpleNames = new HashSet<String>();
 	protected Set<String> baseThrowables = new HashSet<String>();
@@ -230,6 +230,51 @@ public class Java2TypeScriptAdapter<C extends JSweetContext> extends AbstractPri
 
 	}
 
+	/**
+	 * Adds a type mapping so that this adapter substitutes the source type with
+	 * the target type during the transpilation process.
+	 * 
+	 * @param sourceTypeName
+	 *            the fully qualified name of the type to be substituted
+	 * @param targetTypeName
+	 *            the fully Qualified name of the type the source type is mapped
+	 *            to
+	 */
+	public void addTypeMapping(String sourceTypeName, String targetTypeName) {
+		typesMapping.put(sourceTypeName, targetTypeName);
+	}
+
+	/**
+	 * Adds a set of name-based type mappings. This method is equivalent to
+	 * calling {@link #addTypeMapping(String, String)} for each entry of the
+	 * given map.
+	 */
+	public void addTypeMappings(Map<String, String> nameMappings) {
+		typesMapping.putAll(nameMappings);
+	}
+
+	/**
+	 * Returns true if the given type name is mapped through the
+	 * {@link #addTypeMapping(String, String)} or
+	 * {@link #addTypeMapping(String, String)} function.
+	 */
+	public boolean isMappedType(String sourceTypeName) {
+		return typesMapping.containsKey(sourceTypeName);
+	}
+
+	/**
+	 * Adds a type mapping so that this adapter substitutes the source type tree
+	 * with a target type during the transpilation process.
+	 * 
+	 * @param mappingFunction
+	 *            a function that takes the type tree, the type name, and
+	 *            returns a substitution (either under the form of a string, or
+	 *            of a string, or of another type tree).
+	 */
+	public void addTypeMapping(BiFunction<JCTree, String, Object> mappingFunction) {
+		complexTypesMapping.add(mappingFunction);
+	}
+
 	@Override
 	public String needsImport(JCImport importDecl, String qualifiedName) {
 		if (isJSweetPath(qualifiedName) || typesMapping.containsKey(qualifiedName)
diff --git a/transpiler/src/main/java/org/jsweet/transpiler/util/AbstractPrinterAdapter.java b/transpiler/src/main/java/org/jsweet/transpiler/util/AbstractPrinterAdapter.java
index fff42da9..9d76635f 100644
--- a/transpiler/src/main/java/org/jsweet/transpiler/util/AbstractPrinterAdapter.java
+++ b/transpiler/src/main/java/org/jsweet/transpiler/util/AbstractPrinterAdapter.java
@@ -440,7 +440,7 @@ public abstract class AbstractPrinterAdapter<C extends JSweetContext> {
 	 * @return the adapted comment (null will remove the JavaDoc comment)
 	 */
 	public String adaptDocComment(JCTree element, String commentText) {
-		return commentText;
+		return parentAdapter == null ? commentText : parentAdapter.adaptDocComment(element, commentText);
 	}
 
 	/**