diff --git a/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt b/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt
index e85e5f838f..0e5f1c5053 100644
--- a/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt
+++ b/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt
@@ -19,7 +19,6 @@ import java.io.IOException
 import java.io.InputStream
 import java.net.*
 import java.util.*
-import java.util.jar.JarInputStream
 
 /**
  * A custom ClassLoader that knows how to load classes from a set of attachments. The attachments themselves only
@@ -318,14 +317,14 @@ object AttachmentsClassLoaderBuilder {
                                               isAttachmentTrusted: (Attachment) -> Boolean,
                                               parent: ClassLoader = ClassLoader.getSystemClassLoader(),
                                               block: (ClassLoader) -> T): T {
-        val attachmentIds = attachments.map { it.id }.toSet()
+        val attachmentIds = attachments.map(Attachment::id).toSet()
 
         val serializationContext = cache.computeIfAbsent(Key(attachmentIds, params)) {
             // Create classloader and load serializers, whitelisted classes
             val transactionClassLoader = AttachmentsClassLoader(attachments, params, txId, isAttachmentTrusted, parent)
             val serializers = createInstancesOfClassesImplementing(transactionClassLoader, SerializationCustomSerializer::class.java)
             val whitelistedClasses = ServiceLoader.load(SerializationWhitelist::class.java, transactionClassLoader)
-                    .flatMap { it.whitelist }
+                    .flatMap(SerializationWhitelist::whitelist)
                     .toList()
 
             // Create a new serializationContext for the current transaction. In this context we will forbid
diff --git a/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt b/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
index a7f9e34a31..fcfdf7a240 100644
--- a/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
+++ b/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
@@ -151,7 +151,7 @@ private constructor(
         // Switch thread local deserialization context to using a cached attachments classloader. This classloader enforces various rules
         // like no-overlap, package namespace ownership and (in future) deterministic Java.
         return AttachmentsClassLoaderBuilder.withAttachmentsClassloaderContext(
-                this.attachments + extraAttachments,
+                attachments + extraAttachments,
                 getParamsWithGoo(),
                 id,
                 isAttachmentTrusted = isAttachmentTrusted) { transactionClassLoader ->