ServiceLoader + Plugin class loader

bridge/src/main/resources/META-INF/services/com.github.sbt.avro.AvroCompiler

@@ -0,0 +1 @@
+com.github.sbt.avro.AvroCompilerBridge

plugin/src/main/scala/com/github/sbt/avro/AvroCompilerPluginClassLoader.scala

@@ -0,0 +1,21 @@
+package com.github.sbt.avro
+
+import java.net.{URL, URLClassLoader}
+
+private object AvroCompilerPluginClassLoader {
+  private val JvmPrefixes = Array("java.", "jdk.")
+  private val CompilerInterface = classOf[AvroCompiler].getName
+}
+
+private class AvroCompilerPluginClassLoader(urls: Array[URL], parent: ClassLoader)
+    extends URLClassLoader(urls) {
+  import AvroCompilerPluginClassLoader.*
+
+  override def findClass(name: String): Class[?] = {
+    if (JvmPrefixes.exists(name.startsWith) || CompilerInterface == name) {
+      parent.loadClass(name)
+    } else {
+      super.findClass(name)
+    }
+  }
+}

plugin/src/main/scala/com/github/sbt/avro/SbtAvro.scala

@@ -7,6 +7,7 @@ import PluginCompat.*
 import sbt.librarymanagement.DependencyFilter
 
 import java.io.File
+import java.util.ServiceLoader
 
 /** Plugin for generating the Java sources for Avro schemas and protocols. */
 object SbtAvro extends AutoPlugin {
@@ -244,19 +245,18 @@ object SbtAvro extends AutoPlugin {
                 // - output files are missing
 
                 // TODO Cache class loader
-                val avroClassLoader = new ChildFirstClassLoader(
+                val avroClassLoader = new AvroCompilerPluginClassLoader(
                   (AvroCompiler / dependencyClasspath).value
                     .map(toNioPath)
                     .map(_.toUri.toURL)
                     .toArray,
                   this.getClass.getClassLoader
                 )
 
-                val compiler = avroClassLoader
-                  .loadClass(avroCompiler.value)
-                  .getDeclaredConstructor()
-                  .newInstance()
-                  .asInstanceOf[AvroCompiler]
+                val compiler = ServiceLoader
+                  .load(classOf[AvroCompiler], avroClassLoader)
+                  .iterator()
+                  .next()
 
                 compiler.setStringType(avroStringType.value)
                 compiler.setFieldVisibility(avroFieldVisibility.value.toUpperCase)