Migrate ant based serial library to Gradle

java/libraries/serial/build.gradle.kts

@@ -1 +1,39 @@
-ant.importBuild("build.xml")
+plugins {
+    java
+}
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(17))
+    }
+}
+
+val coreJarPath = layout.projectDirectory.file("../../../core/library/core.jar")
+val jsscJarPath = layout.projectDirectory.file("library/jssc.jar")
+val binDir = layout.projectDirectory.dir("bin")
+val serialJarOutputDir = layout.projectDirectory.dir("library")
+
+dependencies {
+    implementation(files(coreJarPath))
+    implementation(files(jsscJarPath))
+}
+
+tasks.register("checkCore") {
+    doFirst {
+        if (!coreJarPath.asFile.exists()) {
+            throw GradleException("Missing core.jar at $coreJarPath. Please build the core module first.")
+        }
+    }
+}
+
+tasks.register<Jar>("buildSerial") {
+    dependsOn("checkCore")
+    archiveFileName.set("serial.jar")
+    destinationDirectory.set(file("library"))
+    from(sourceSets.main.get().output)
+}
+
+tasks.named<Delete>("clean") {
+    delete(binDir)
+    delete(serialJarOutputDir.file("serial.jar"))
+}