diff --git a/build.gradle b/build.gradle
index ac0995e4ea..aeccb9ada0 100644
--- a/build.gradle
+++ b/build.gradle
@@ -124,6 +124,8 @@ buildscript {
     ext.commons_configuration2_version = constants.getProperty("commonsConfiguration2Version")
     ext.commons_text_version = constants.getProperty("commonsTextVersion")
     ext.snake_yaml_version = constants.getProperty("snakeYamlVersion")
+    ext.javaassist_version = constants.getProperty("javaassistVersion")
+
     if (JavaVersion.current().isJava8()) {
         ext.fontawesomefx_commons_version = constants.getProperty("fontawesomefxCommonsJava8Version")
         ext.fontawesomefx_fontawesome_version = constants.getProperty("fontawesomefxFontawesomeJava8Version")
diff --git a/constants.properties b/constants.properties
index 6c78be4da5..5c01bc82b7 100644
--- a/constants.properties
+++ b/constants.properties
@@ -106,3 +106,4 @@ fontawesomefxFontawesomeJava8Version=4.7.0-5
 # FontAwesomeFX for a more recent version of the Java Runtime (class file version 55.0)
 fontawesomefxCommonsVersion=11.0
 fontawesomefxFontawesomeVersion=4.7.0-11
+javaassistVersion=3.27.0-GA
diff --git a/experimental/quasar-hook/build.gradle b/experimental/quasar-hook/build.gradle
index dfe49fa970..df09b426d7 100644
--- a/experimental/quasar-hook/build.gradle
+++ b/experimental/quasar-hook/build.gradle
@@ -1,7 +1,3 @@
-ext {
-    javaassist_version = "3.12.1.GA"
-}
-
 apply plugin: 'kotlin'
 apply plugin: 'idea'
 
@@ -10,7 +6,7 @@ description 'A javaagent to allow hooking into the instrumentation by Quasar'
 dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
     compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
-    compile "javassist:javassist:$javaassist_version"
+    compile "org.javassist:javassist:$javaassist_version"
 }
 
 jar {
diff --git a/tools/checkpoint-agent/build.gradle b/tools/checkpoint-agent/build.gradle
index 228a6de595..838d70c652 100644
--- a/tools/checkpoint-agent/build.gradle
+++ b/tools/checkpoint-agent/build.gradle
@@ -1,28 +1,3 @@
-buildscript {
-    // For sharing constants between builds
-    Properties constants = new Properties()
-    file("$projectDir/../../constants.properties").withInputStream { constants.load(it) }
-
-    ext.kotlin_version = constants.getProperty("kotlinVersion")
-    ext.javaassist_version = "3.12.1.GA"
-
-    repositories {
-        mavenLocal()
-        mavenCentral()
-        jcenter()
-    }
-
-    dependencies {
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-    }
-}
-
-repositories {
-    mavenLocal()
-    mavenCentral()
-    jcenter()
-}
-
 apply plugin: 'kotlin'
 apply plugin: 'idea'
 apply plugin: 'net.corda.plugins.publish-utils'
@@ -33,7 +8,7 @@ description 'A javaagent to allow hooking into Kryo checkpoints'
 dependencies {
     compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
     compileOnly "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
-    compileOnly "javassist:javassist:$javaassist_version"
+    compileOnly "org.javassist:javassist:$javaassist_version"
     compileOnly "com.esotericsoftware:kryo:$kryo_version"
     compileOnly "co.paralleluniverse:quasar-core:$quasar_version"