From 33670d62b16c58e02f393f050ad1b40093351925 Mon Sep 17 00:00:00 2001
From: Shams Asari <shams.asari@r3.com>
Date: Mon, 31 Dec 2018 13:15:29 +0000
Subject: [PATCH] Closing the app class loader on node shutdown (#4479)

---
 .../net/corda/node/cordapp/CordappLoader.kt   |  2 +-
 .../net/corda/node/internal/AbstractNode.kt   |  4 ++--
 .../cordapp/JarScanningCordappLoader.kt       | 22 +++++++++----------
 3 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/node/src/main/kotlin/net/corda/node/cordapp/CordappLoader.kt b/node/src/main/kotlin/net/corda/node/cordapp/CordappLoader.kt
index 8a8feffc2d..2ecf6dc9d8 100644
--- a/node/src/main/kotlin/net/corda/node/cordapp/CordappLoader.kt
+++ b/node/src/main/kotlin/net/corda/node/cordapp/CordappLoader.kt
@@ -8,7 +8,7 @@ import net.corda.core.schemas.MappedSchema
 /**
  * Handles loading [Cordapp]s.
  */
-interface CordappLoader {
+interface CordappLoader : AutoCloseable {
 
     /**
      * Returns all [Cordapp]s found.
diff --git a/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt b/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt
index c2c5c49207..0dea38f8ef 100644
--- a/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt
+++ b/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt
@@ -145,7 +145,7 @@ abstract class AbstractNode<S>(val configuration: NodeConfiguration,
         }
     }
 
-    val cordappLoader: CordappLoader = makeCordappLoader(configuration, versionInfo)
+    val cordappLoader: CordappLoader = makeCordappLoader(configuration, versionInfo).closeOnStop()
     val schemaService = NodeSchemaService(cordappLoader.cordappSchemas).tokenize()
     val identityService = PersistentIdentityService(cacheFactory).tokenize()
     val database: CordaPersistence = createCordaPersistence(
@@ -544,7 +544,7 @@ abstract class AbstractNode<S>(val configuration: NodeConfiguration,
             generatedCordapps += VirtualCordapp.generateSimpleNotaryCordapp(versionInfo)
         }
         val blacklistedKeys = if (configuration.devMode) emptyList()
-        else configuration.cordappSignerKeyFingerprintBlacklist.mapNotNull {
+        else configuration.cordappSignerKeyFingerprintBlacklist.map {
             try {
                 SecureHash.parse(it)
             } catch (e: IllegalArgumentException) {
diff --git a/node/src/main/kotlin/net/corda/node/internal/cordapp/JarScanningCordappLoader.kt b/node/src/main/kotlin/net/corda/node/internal/cordapp/JarScanningCordappLoader.kt
index 4a319df1eb..d27134880b 100644
--- a/node/src/main/kotlin/net/corda/node/internal/cordapp/JarScanningCordappLoader.kt
+++ b/node/src/main/kotlin/net/corda/node/internal/cordapp/JarScanningCordappLoader.kt
@@ -43,13 +43,6 @@ class JarScanningCordappLoader private constructor(private val cordappJarPaths:
                                                    private val versionInfo: VersionInfo = VersionInfo.UNKNOWN,
                                                    extraCordapps: List<CordappImpl>,
                                                    private val signerKeyFingerprintBlacklist: List<SecureHash.SHA256> = emptyList()) : CordappLoaderTemplate() {
-
-    override val cordapps: List<CordappImpl> by lazy {
-        loadCordapps() + extraCordapps
-    }
-
-    override val appClassLoader: ClassLoader = URLClassLoader(cordappJarPaths.stream().map { it.url }.toTypedArray(), javaClass.classLoader)
-
     init {
         if (cordappJarPaths.isEmpty()) {
             logger.info("No CorDapp paths provided")
@@ -58,6 +51,12 @@ class JarScanningCordappLoader private constructor(private val cordappJarPaths:
         }
     }
 
+    override val cordapps: List<CordappImpl> by lazy { loadCordapps() + extraCordapps }
+
+    override val appClassLoader: URLClassLoader = URLClassLoader(cordappJarPaths.stream().map { it.url }.toTypedArray(), javaClass.classLoader)
+
+    override fun close() = appClassLoader.close()
+
     companion object {
         private val logger = contextLogger()
 
@@ -260,7 +259,10 @@ class JarScanningCordappLoader private constructor(private val cordappJarPaths:
     }
 
     private fun findPlugins(cordappJarPath: RestrictedURL): List<SerializationWhitelist> {
-        return ServiceLoader.load(SerializationWhitelist::class.java, URLClassLoader(arrayOf(cordappJarPath.url), appClassLoader)).toList().filter {
+        val whitelists = URLClassLoader(arrayOf(cordappJarPath.url), appClassLoader).use {
+            ServiceLoader.load(SerializationWhitelist::class.java, it).toList()
+        }
+        return whitelists.filter {
             it.javaClass.location == cordappJarPath.url && it.javaClass.name.startsWith(cordappJarPath.qualifiedNamePrefix)
         } + DefaultWhitelist // Always add the DefaultWhitelist to the whitelist for an app.
     }
@@ -378,8 +380,4 @@ abstract class CordappLoaderTemplate : CordappLoader {
     override val cordappSchemas: Set<MappedSchema> by lazy {
         cordapps.flatMap { it.customSchemas }.toSet()
     }
-
-    override val appClassLoader: ClassLoader by lazy {
-        URLClassLoader(cordapps.stream().map { it.jarPath }.toTypedArray(), javaClass.classLoader)
-    }
 }