BASE-4618: Use JMH benchmark tool

core-java-modules/core-java-lang-4/pom.xml

@@ -16,6 +16,20 @@
         <relativePath>../</relativePath>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
     <build>
         <finalName>core-java-lang-4</finalName>
         <resources>
@@ -26,4 +40,8 @@
         </resources>
     </build>
 
+    <properties>
+        <jmh.version>1.28</jmh.version>
+    </properties>
+      
 </project>

core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/BenchmarkRunner.java

@@ -0,0 +1,34 @@
+package com.baeldung.finalkeyword;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+
+import java.util.concurrent.TimeUnit;
+
+public class BenchmarkRunner {
+
+    public static void main(String[] args) throws Exception {
+        org.openjdk.jmh.Main.main(args);
+    }
+
+    @Benchmark
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    @BenchmarkMode(Mode.AverageTime)
+    public static String concatNonFinalStrings() {
+        String x = "x";
+        String y = "y";
+        return x + y;
+    }
+
+    @Benchmark
+    @OutputTimeUnit(TimeUnit.NANOSECONDS)
+    @BenchmarkMode(Mode.AverageTime)
+    public static String concatFinalStrings() {
+        final String x = "x";
+        final String y = "y";
+        return x + y;
+    }
+
+}

core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/LocalVariableFinal.java

@@ -1,22 +0,0 @@
-package com.baeldung.finalkeyword;
-
-public class LocalVariableFinal {
-
-    public static void main(String[] args) {
-        for (int i = 0; i < 1500; i++) {
-            long startTime = System.nanoTime();
-            String result = concatStrings();
-            long totalTime = System.nanoTime() - startTime;
-            if (i >= 500) {
-                System.out.println(totalTime);
-            }
-        }
-    }
-
-    private static String concatStrings() {
-        final String x = "x";
-        final String y = "y";
-        return x + y;
-    }
-
-}

core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/LocalVariableNonFinal.java

@@ -1,22 +0,0 @@
-package com.baeldung.finalkeyword;
-
-public class LocalVariableNonFinal {
-
-    public static void main(String[] args) {
-        for (int i = 0; i < 1500; i++) {
-            long startTime = System.nanoTime();
-            String result = concatStrings();
-            long totalTime = System.nanoTime() - startTime;
-            if (i >= 500) {
-                System.out.println(totalTime);
-            }
-        }
-    }
-
-    private static String concatStrings() {
-        String x = "x";
-        String y = "y";
-        return x + y;
-    }
-
-}