diff --git a/injector-plugin/build.gradle b/injector-plugin/build.gradle
index 745807236e..088fdf8ebd 100644
--- a/injector-plugin/build.gradle
+++ b/injector-plugin/build.gradle
@@ -39,7 +39,7 @@ compileJava.doLast() {
         into "$buildDir"
     }
     def path = sourceSets.main.runtimeClasspath
-    def loader = new URLClassLoader(path.collect { f -> f.toURL() } as URL[])
+    def loader = new URLClassLoader(path.collect { f -> f.toURI().toURL() } as URL[])
     def inject = loader.loadClass('net.runelite.injector.Injector')
     String[] jarPaths = [
             deobfuscatedJar.toString(),
@@ -47,6 +47,7 @@ compileJava.doLast() {
             injectedClassesPath.toString()
     ]
     inject.main(jarPaths)
+    loader.close()
 }
 
 test {
diff --git a/runelite-script-assembler-plugin/build.gradle b/runelite-script-assembler-plugin/build.gradle
index 165c0a3d4d..4720641d75 100644
--- a/runelite-script-assembler-plugin/build.gradle
+++ b/runelite-script-assembler-plugin/build.gradle
@@ -13,7 +13,7 @@ compileJava.outputs.upToDateWhen {false}
 
 compileJava.doLast {
     def path = sourceSets.main.runtimeClasspath
-    def loader = new URLClassLoader(path.collect { f -> f.toURL() } as URL[])
+    def loader = new URLClassLoader(path.collect { f -> f.toURI().toURL() } as URL[])
     def assemble = loader.loadClass('net.runelite.script.AssembleMojo')
     String[] assembleArgs = [
             "${project.rootDir}/runelite-client/src/main/scripts",
@@ -27,4 +27,6 @@ compileJava.doLast {
             "${project.rootDir}/runelite-client/src/main/resources/runelite/index"
     ]
     index.main(indexArgs)
+
+    loader.close()
 }