chore: improve install4j gradle task

build.gradle.kts

@@ -1,10 +1,10 @@
 import com.github.breadmoirai.githubreleaseplugin.GithubReleaseTask
 import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+import com.install4j.gradle.Install4jTask
 import org.gradle.internal.os.OperatingSystem
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 import java.io.IOException
 import java.util.*
-import com.install4j.gradle.Install4jTask
 
 val isUnstable = properties["release"] == null
 var commitNumber: String = ""
@@ -27,14 +27,6 @@ plugins {
 	id("com.install4j.gradle") version "8.0"
 }
 
-install4j {
-	if (hasProperty("install4jDir")) {
-		(property("install4jDir") as String?)?.let {
-			installDir = file(it)
-		}
-	}
-}
-
 // source directories
 sourceSets {
 	main {
@@ -90,6 +82,11 @@ githubRelease {
 	token(project.properties["github.token"]?.toString())
 }
 
+install4j {
+	(properties["install4j.installDir"] as String?)?.let { installDir = file(it) }
+	(properties["install4j.license"] as String?)?.let { license = it }
+}
+
 val MAIN = "_main"
 tasks {
 
@@ -145,23 +142,18 @@ tasks {
 		dependsOn(shadowJar)
 		group = MAIN
 
-		var path : File? = null
+		projectFile = file("MonsterUtilities.install4j")
+		destination = "build/install4j/"
+		this.release = version.toString()
+
+		lateinit var jarTemp: File
 		doFirst {
-			path = file(jarFile).copyTo(file("build/install4j/$jarFile"), true)
-			if (path?.exists() == false) {
-				println("Couldn't create temporary install4j file '${path?.path}'")
-			}
+			jarTemp = file(jarFile).copyTo(file("build/install4j/$jarFile"), true)
 		}
-
 		doLast {
-			if (path?.delete() == false) {
-				println("Cannot delete temporary install4j file '${path?.path}'")
-			}
+			if(!jarTemp.delete())
+				println("Couldn't delete temporary install4j file '${jarTemp.path}'")
 		}
-
-		projectFile = file("MonsterUtilities.install4j")
-		this.release = version.toString()
-		destination = "build/install4j/"
 	}
 
 	withType<KotlinCompile> {