diff --git a/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/MarshallingContexts.java b/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/MarshallingContexts.java
index 917d1b8c8..7073d9085 100644
--- a/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/MarshallingContexts.java
+++ b/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/MarshallingContexts.java
@@ -25,7 +25,9 @@
 /**
  * Providers of marshalling contexts.
  */
-public interface MarshallingContexts {
+public final class MarshallingContexts {
+
+	private MarshallingContexts() {}
 
 	/**
 	 * Yields a marshalling context that writes to the given output stream.
@@ -34,7 +36,7 @@ public interface MarshallingContexts {
 	 * @return the marshalling context
 	 * @throws IOException if the context cannot be created
 	 */
-	static MarshallingContext of(OutputStream os) throws IOException {
+	public static MarshallingContext of(OutputStream os) throws IOException {
 		return new MarshallingContextImpl(os);
 	}
 }
\ No newline at end of file
diff --git a/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/UnmarshallingContexts.java b/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/UnmarshallingContexts.java
index e1304168c..0c7da372c 100644
--- a/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/UnmarshallingContexts.java
+++ b/io-hotmoka-marshalling/src/main/java/io/hotmoka/marshalling/UnmarshallingContexts.java
@@ -25,7 +25,9 @@
 /**
  * Providers of unmarshalling contexts.
  */
-public interface UnmarshallingContexts {
+public final class UnmarshallingContexts {
+
+	private UnmarshallingContexts() {}
 
 	/**
 	 * Creates an unmarshalling context.
@@ -33,7 +35,7 @@ public interface UnmarshallingContexts {
 	 * @param is the input stream of the context
 	 * @throws IOException if the context cannot be created
 	 */
-	static UnmarshallingContext of(InputStream is) throws IOException {
+	public static UnmarshallingContext of(InputStream is) throws IOException {
 		return new UnmarshallingContextImpl(is);
 	}
 }
\ No newline at end of file
diff --git a/io-hotmoka-node/src/main/java/io/hotmoka/node/internal/ConsensusConfigImpl.java b/io-hotmoka-node/src/main/java/io/hotmoka/node/internal/ConsensusConfigImpl.java
index 055c05984..92c3b57b2 100644
--- a/io-hotmoka-node/src/main/java/io/hotmoka/node/internal/ConsensusConfigImpl.java
+++ b/io-hotmoka-node/src/main/java/io/hotmoka/node/internal/ConsensusConfigImpl.java
@@ -616,10 +616,9 @@ protected ConsensusConfigBuilderImpl(Toml toml) throws NoSuchAlgorithmException
 			if (maxErrorLength != null)
 				setMaxErrorLength(maxErrorLength);
 
-			// TODO: remove all type conversions below
 			var maxDependencies = toml.getLong("max_dependencies");
 			if (maxDependencies != null)
-				setMaxDependencies((int) (long) maxDependencies);
+				setMaxDependencies(maxDependencies);
 
 			var maxCumulativeSizeOfDependencies = toml.getLong("max_cumulative_size_of_dependencies");
 			if (maxCumulativeSizeOfDependencies != null)
diff --git a/io-hotmoka-verification/src/main/java/io/hotmoka/verification/TakamakaClassLoaders.java b/io-hotmoka-verification/src/main/java/io/hotmoka/verification/TakamakaClassLoaders.java
index 705129a5a..7a2442bf0 100644
--- a/io-hotmoka-verification/src/main/java/io/hotmoka/verification/TakamakaClassLoaders.java
+++ b/io-hotmoka-verification/src/main/java/io/hotmoka/verification/TakamakaClassLoaders.java
@@ -24,7 +24,9 @@
 /**
  * A provider of class loaders used to access the definition of the classes of a Takamaka program.
  */
-public interface TakamakaClassLoaders {
+public final class TakamakaClassLoaders {
+
+	private TakamakaClassLoaders() {}
 
 	/**
 	 * Yields a class loader with the given jars, given as byte arrays.
@@ -35,7 +37,7 @@ public interface TakamakaClassLoaders {
 	 * @return the class loader
 	 * @throws ClassNotFoundException if some class of the Takamaka runtime cannot be loaded
 	 */
-	static TakamakaClassLoader of(Stream<byte[]> jars, long verificationVersion) throws ClassNotFoundException {
+	public static TakamakaClassLoader of(Stream<byte[]> jars, long verificationVersion) throws ClassNotFoundException {
 		return new TakamakaClassLoaderImpl(jars, verificationVersion);
 	}
 }
\ No newline at end of file
diff --git a/io-hotmoka-verification/src/main/java/io/hotmoka/verification/VerifiedJars.java b/io-hotmoka-verification/src/main/java/io/hotmoka/verification/VerifiedJars.java
index 439e9c247..2d5df4bfd 100644
--- a/io-hotmoka-verification/src/main/java/io/hotmoka/verification/VerifiedJars.java
+++ b/io-hotmoka-verification/src/main/java/io/hotmoka/verification/VerifiedJars.java
@@ -25,7 +25,9 @@
 /**
  * A provider of jars that have undergone static verification, before being installed into blockchain.
  */
-public interface VerifiedJars {
+public final class VerifiedJars {
+
+	private VerifiedJars() {}
 
 	/**
 	 * Creates a verified jar from the given file. This verification
@@ -43,7 +45,7 @@ public interface VerifiedJars {
 	 * @throws ClassNotFoundException if some class of the Takamaka program cannot be loaded
 	 * @throws UnsupportedVerificationVersionException if the verification version is not available
 	 */
-	static VerifiedJar of(byte[] jar, TakamakaClassLoader classLoader, boolean duringInitialization, boolean allowSelfCharged, boolean skipsVerification) throws IOException, ClassNotFoundException, UnsupportedVerificationVersionException {
+	public static VerifiedJar of(byte[] jar, TakamakaClassLoader classLoader, boolean duringInitialization, boolean allowSelfCharged, boolean skipsVerification) throws IOException, ClassNotFoundException, UnsupportedVerificationVersionException {
 		return new VerifiedJarImpl(jar, classLoader, duringInitialization, allowSelfCharged, skipsVerification);
 	}
 }
\ No newline at end of file
diff --git a/io-hotmoka-whitelisting/src/main/java/io/hotmoka/whitelisting/ResolvingClassLoaders.java b/io-hotmoka-whitelisting/src/main/java/io/hotmoka/whitelisting/ResolvingClassLoaders.java
index 12ff3fb86..3549919f4 100644
--- a/io-hotmoka-whitelisting/src/main/java/io/hotmoka/whitelisting/ResolvingClassLoaders.java
+++ b/io-hotmoka-whitelisting/src/main/java/io/hotmoka/whitelisting/ResolvingClassLoaders.java
@@ -24,7 +24,9 @@
 /**
  * A provider of resolving class loaders.
  */
-public interface ResolvingClassLoaders {
+public final class ResolvingClassLoaders {
+
+	private ResolvingClassLoaders() {}
 
 	/**
 	 * Yields a resolving class loader that loads classes from the given jars, provided as byte arrays.
@@ -34,7 +36,7 @@ public interface ResolvingClassLoaders {
 	 *                            set of white-listing annotations used by the class loader
 	 * @return the class loader
 	 */
-	static ResolvingClassLoader of(Stream<byte[]> jars, long verificationVersion) {
+	public static ResolvingClassLoader of(Stream<byte[]> jars, long verificationVersion) {
 		return new ResolvingClassLoaderImpl(jars, verificationVersion);
 	}
 }
\ No newline at end of file