Code review from @orangy.

src/main/kotlin/com/beust/kobalt/Plugins.kt

@@ -186,13 +186,7 @@ public class Plugins @Inject constructor (val taskManagerProvider : Provider<Tas
     }
 
     val allTasks : List<PluginTask>
-        get() {
-            val result = arrayListOf<PluginTask>()
-            Plugins.plugins.forEach { plugin ->
-                result.addAll(plugin.tasks)
-            }
-            return result
-    }
+        get() = Plugins.plugins.flatMap { it.tasks }
 
     fun installPlugins(dependencies: List<IClasspathDependency>, classLoader: ClassLoader) {
         val executor = executors.newExecutor("Plugins", 5)

src/main/kotlin/com/beust/kobalt/api/Kobalt.kt

@@ -48,8 +48,7 @@ public class Kobalt {
         private val KOBALT_PROPERTIES = "kobalt.properties"
         private val LOCAL_PROPERTIES = "local.properties"
 
-        private val properties : Properties
-            get() = readProperties()
+        private val properties : Properties by lazy { readProperties() }
 
         private fun readProperties() : Properties {
             val result = Properties()
@@ -59,13 +58,13 @@ public class Kobalt {
             if (url != null) {
                 readProperties(result, url.openConnection().inputStream)
             } else {
-                throw IllegalArgumentException("Couldn't find ${KOBALT_PROPERTIES}")
+                throw AssertionError("Couldn't find $KOBALT_PROPERTIES")
             }
 
             // local.properties can be used by external users
             Paths.get(LOCAL_PROPERTIES).let { path ->
                 if (Files.exists(path)) {
-                    Files.newInputStream(path).let {
+                    Files.newInputStream(path).use {
                         readProperties(result, it)
                     }
                 }

src/main/kotlin/com/beust/kobalt/api/Plugin.kt

@@ -23,9 +23,9 @@ public interface Plugin {
     }
 
     fun addTask(project: Project, name: String, description: String = "",
-            runBefore: List<String> = arrayListOf<String>(),
-            runAfter: List<String> = arrayListOf<String>(),
-            alwaysRunAfter: List<String> = arrayListOf<String>(),
+            runBefore: List<String> = listOf<String>(),
+            runAfter: List<String> = listOf<String>(),
+            alwaysRunAfter: List<String> = listOf<String>(),
             task: (Project) -> TaskResult) {
         tasks.add(
             object : BasePluginTask(this, name, description, project) {

src/main/kotlin/com/beust/kobalt/api/PluginProperties.kt

@@ -10,14 +10,8 @@ import java.util.*
 class PluginProperties @Inject constructor() {
     private val pluginProperties = hashMapOf<String, HashMap<String, Any>>()
 
-    fun put(pluginName: String, key: String, value: Any) {
-        var map = pluginProperties[pluginName]
-        if (map == null) {
-            map = hashMapOf<String, Any>()
-            pluginProperties.put(pluginName, map)
-        }
-        map.put(key, value)
-    }
+    fun put(pluginName: String, key: String, value: Any) =
+        pluginProperties.getOrPut(pluginName) { hashMapOf<String, Any>() }.put(key, value)
 
     fun get(pluginName: String, key: String) = pluginProperties[pluginName]?.get(key)
 }

src/main/kotlin/com/beust/kobalt/misc/ToString.kt

@@ -1,11 +1,11 @@
 package com.beust.kobalt.misc
 
-fun toString<T>(name: String, vararg o: T) : String {
-    val sb = StringBuffer()
+fun <T> toString(name: String, vararg o: T) : String {
+    val sb = StringBuilder()
 
     for (i in 0..o.size - 1 step 2) {
         if (i > 0) sb.append(", ")
-        sb.append(o.get(i).toString() + ":" + o.get(i + 1))
+        sb.append(o[i].toString() + ":" + o[i + 1])
     }
     return "{$name $sb}"
 }