Use Gradle Kotlin DSL

minecraft/libraries/log4j-patch/build.gradle.kts

@@ -0,0 +1,53 @@
+import java.io.RandomAccessFile
+
+version = "1.0"
+
+sourceSets.create("agent") {
+    java {
+        srcDir("src/main/agent")
+    }
+}
+
+dependencies {
+    compileOnly("org.apache.logging.log4j:log4j-core:2.0-beta9")
+}
+
+tasks.withType<JavaCompile> {
+    sourceCompatibility = "1.8"
+    targetCompatibility = "1.8"
+
+    doLast {
+        val tree = fileTree(destinationDirectory)
+        tree.include("**/*.class")
+        tree.exclude("module-info.class")
+        tree.forEach {
+            RandomAccessFile(it, "rw").use { rf ->
+                rf.seek(7)   // major version
+                rf.write(50)   // java 6
+                rf.close()
+            }
+        }
+    }
+}
+
+val agentJar = tasks.create<Jar>("agentJar") {
+    dependsOn(tasks.compileJava)
+
+    archiveBaseName.set("log4j-patch-agent")
+
+    manifest {
+        attributes("Premain-Class" to "org.glavo.log4j.patch.agent.Log4jAgent")
+    }
+
+    from(sourceSets["agent"].output)
+    from(sourceSets["main"].output) {
+        includeEmptyDirs = false
+        eachFile { path = "org/glavo/log4j/patch/agent/$name.bin" }
+    }
+
+}
+
+tasks.jar {
+    enabled = false
+    dependsOn(agentJar)
+}