Data commit

Task/Introspection/Kotlin/introspection.kotlin

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+// version 1.0.6 (intro.kt)
+
+import java.lang.reflect.Method
+
+val bloop = -3
+val i = 4
+val j = 5
+val k = 6
+
+fun main(args: Array<String>) {
+    // get version of JVM
+    val version = System.getProperty("java.version")
+    if (version >= "1.6") println("The current JVM version is $version")
+    else println("Must use version 1.6 or later")
+
+    // check that 'bloop' and 'Math.abs' are available
+    // note that the class created by the Kotlin compiler for top level declarations will be called 'IntroKt'
+    val topLevel = Class.forName("IntroKt")
+    val math = Class.forName("java.lang.Math")
+    val abs = math.getDeclaredMethod("abs", Int::class.java)
+    val methods = topLevel.getDeclaredMethods()
+    for (method in methods) {
+        // note that the read-only Kotlin property 'bloop' is converted to the static method 'getBloop' in Java
+        if (method.name == "getBloop" && method.returnType == Int::class.java) {
+            println("\nabs(bloop) = ${abs.invoke(null, method.invoke(null))}")
+            break
+        }
+    }
+
+    // now get the number of global integer variables and their sum
+    var count = 0
+    var sum = 0
+    for (method in methods) {
+        if (method.returnType == Int::class.java) {
+            count++
+            sum += method.invoke(null) as Int
+        }
+    }
+    println("\nThere are $count global integer variables and their sum is $sum")
+}