Merge pull request #7666 from macieg/bael-3192

BAEL-3192 | A guide to System.gc()

core-java-modules/core-java-jvm/src/main/java/com/baeldung/systemgc/DemoApplication.java

@@ -0,0 +1,33 @@
+package com.baeldung.systemgc;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Scanner;
+
+import static java.util.UUID.randomUUID;
+
+public class DemoApplication {
+
+    private static final Map<String, String> cache = new HashMap<String, String>();
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        while (scanner.hasNext()) {
+            final String next = scanner.next();
+            if ("fill".equals(next)) {
+                for (int i = 0; i < 1000000; i++) {
+                    cache.put(randomUUID().toString(), randomUUID().toString());
+                }
+            } else if ("invalidate".equals(next)) {
+                cache.clear();
+            } else if ("gc".equals(next)) {
+                System.gc();
+            } else if ("exit".equals(next)) {
+                System.exit(0);
+            } else {
+                System.out.println("unknown");
+            }
+        }
+    }
+}