diff --git a/libs/corda-sdk/src/main/kotlin/net/corda/sdk/packaging/KeyStoreHelper.kt b/libs/corda-sdk/src/main/kotlin/net/corda/sdk/packaging/KeyStoreHelper.kt
index a135aa61d9b..819d68f6539 100644
--- a/libs/corda-sdk/src/main/kotlin/net/corda/sdk/packaging/KeyStoreHelper.kt
+++ b/libs/corda-sdk/src/main/kotlin/net/corda/sdk/packaging/KeyStoreHelper.kt
@@ -85,15 +85,18 @@ class KeyStoreHelper {
         certificateAlias: String,
         certificateFactoryType: String = "X.509"
     ) {
-        val keyStore = KeyStore.getInstance(KEYSTORE_INSTANCE_TYPE)
-        keyStore.load(keyStoreFile.inputStream(), keyStorePassword.toCharArray())
-        keyStore.setCertificateEntry(
-            certificateAlias,
-            CertificateFactory.getInstance(certificateFactoryType)
-                .generateCertificate(certificateInputStream),
-        )
-        keyStoreFile.outputStream().use {
-            keyStore.store(it, keyStorePassword.toCharArray())
+        keyStoreFile.inputStream().use { inputStream ->
+            val keyStore = KeyStore.getInstance(KEYSTORE_INSTANCE_TYPE)
+            keyStore.load(inputStream, keyStorePassword.toCharArray())
+            keyStore.setCertificateEntry(
+                certificateAlias,
+                CertificateFactory.getInstance(certificateFactoryType)
+                    .generateCertificate(certificateInputStream),
+            )
+
+            keyStoreFile.outputStream().use { outputStream ->
+                keyStore.store(outputStream, keyStorePassword.toCharArray())
+            }
         }
     }
 
@@ -110,15 +113,18 @@ class KeyStoreHelper {
         certificateAlias: String,
         exportedCertFile: File
     ) {
-        val keyStore = KeyStore.getInstance(KEYSTORE_INSTANCE_TYPE)
-        keyStore.load(keyStoreFile.inputStream(), keyStorePassword.toCharArray())
-        val cert = keyStore.getCertificate(certificateAlias)
-        val writer = StringWriter()
-        PemWriter(writer).use { pw ->
-            val gen: PemObjectGenerator = JcaMiscPEMGenerator(cert)
-            pw.writeObject(gen)
+        keyStoreFile.inputStream().use {
+            val keyStore = KeyStore.getInstance(KEYSTORE_INSTANCE_TYPE)
+            keyStore.load(it, keyStorePassword.toCharArray())
+            val cert = keyStore.getCertificate(certificateAlias)
+            StringWriter().use { sw ->
+                PemWriter(sw).use { pw ->
+                    val gen: PemObjectGenerator = JcaMiscPEMGenerator(cert)
+                    pw.writeObject(gen)
+                }
+                exportedCertFile.writeText(sw.toString())
+            }
         }
-        exportedCertFile.writeText(writer.toString())
     }
 
     /**
diff --git a/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/configuration/NetworkConfig.kt b/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/configuration/NetworkConfig.kt
index 1d37e199d9d..ebcae483536 100644
--- a/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/configuration/NetworkConfig.kt
+++ b/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/configuration/NetworkConfig.kt
@@ -20,8 +20,9 @@ class NetworkConfig(val configFilePath: String) {
     init {
         val mapper = ObjectMapper()
         vNodes = try {
-            val fis = FileInputStream(configFilePath)
-            mapper.readValue(fis, object : TypeReference<List<VNode>>() {})
+            FileInputStream(configFilePath).use {
+                mapper.readValue(it, object : TypeReference<List<VNode>>() {})
+            }
         } catch (e: Exception) {
             throw CordaRuntimeGradlePluginException("Failed to read network configuration file, with exception: $e")
         }
diff --git a/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/cordapp/CordappTasksImpl.kt b/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/cordapp/CordappTasksImpl.kt
index 10c21529726..d374471ce86 100644
--- a/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/cordapp/CordappTasksImpl.kt
+++ b/tools/corda-runtime-gradle-plugin/src/main/kotlin/net/corda/gradle/plugin/cordapp/CordappTasksImpl.kt
@@ -51,10 +51,11 @@ class CordappTasksImpl(var pc: ProjectContext) {
     private fun validateGroupPolicy() {
         val groupPolicyFile = File(pc.groupPolicyFilePath)
         val groupPolicy = try {
-            val fis = FileInputStream(groupPolicyFile)
             val mapper = ObjectMapper()
             mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
-            mapper.readValue(fis, GroupPolicyDTO::class.java)
+            FileInputStream(groupPolicyFile).use { fis ->
+                mapper.readValue(fis, GroupPolicyDTO::class.java)
+            }
         } catch (e: Exception) {
             throw CordaRuntimeGradlePluginException("Failed to read GroupPolicy from group policy file with exception: $e.", e)
         }
@@ -93,19 +94,23 @@ class CordappTasksImpl(var pc: ProjectContext) {
                 password = pc.keystorePassword
             )
             pc.logger.quiet("Importing default gradle certificate")
-            KeyStoreHelper().importCertificateIntoKeyStore(
-                keyStoreFile = keystoreFile,
-                keyStorePassword = pc.keystorePassword,
-                certificateInputStream = File(pc.gradleDefaultCertFilePath).inputStream(),
-                certificateAlias = pc.gradleDefaultCertAlias
-            )
+            File(pc.gradleDefaultCertFilePath).inputStream().use {
+                KeyStoreHelper().importCertificateIntoKeyStore(
+                    keyStoreFile = keystoreFile,
+                    keyStorePassword = pc.keystorePassword,
+                    certificateInputStream = it,
+                    certificateAlias = pc.gradleDefaultCertAlias
+                )
+            }
             pc.logger.quiet("Importing R3 signing certificate")
-            KeyStoreHelper().importCertificateIntoKeyStore(
-                keyStoreFile = keystoreFile,
-                keyStorePassword = pc.keystorePassword,
-                certificateInputStream = File(pc.r3RootCertFile).inputStream(),
-                certificateAlias = pc.r3RootCertKeyAlias
-            )
+            File(pc.r3RootCertFile).inputStream().use {
+                KeyStoreHelper().importCertificateIntoKeyStore(
+                    keyStoreFile = keystoreFile,
+                    keyStorePassword = pc.keystorePassword,
+                    certificateInputStream = it,
+                    certificateAlias = pc.r3RootCertKeyAlias
+                )
+            }
 
             KeyStoreHelper().exportCertificateFromKeyStore(
                 keyStoreFile = keystoreFile,