6.3. Статические вложенные классы;

https://job4j.ru/profile/exercise/20/task-view/1031

src/main/java/ru/j4j/oop/Calc.java

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+package ru.j4j.oop;
+
+public class Calc {
+
+    public static class Multiple {
+
+        private final int rsl;
+
+        public Multiple(int number) {
+            rsl = number;
+        }
+
+        public int getResult() {
+            return rsl;
+        }
+
+    }
+
+    public static Multiple getMult(int value) {
+        int result = value * value;
+        return new Multiple(result);
+    }
+
+    public static void main(String[] args) {
+        Calc.Multiple mult = Calc.getMult(3);
+        System.out.println("Квадрат числа равен " + mult.getResult());
+    }
+}

src/main/java/ru/j4j/oop/StNested.java

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+package ru.j4j.oop;
+
+public class StNested {
+
+    private static int num1;
+    public int num2;
+
+    public StNested() {
+    }
+
+    static class StaticNested {
+
+        void setStaticOuterVariable(int value) {
+            num1 = value;
+        }
+
+    }
+
+    public static void main(String[] args) {
+        num1 = 1;
+        StaticNested nested = new StaticNested();
+        nested.setStaticOuterVariable(2);
+        System.out.println("num1 = " + num1);
+    }
+}