diff --git a/core-java-modules/core-java-lang-4/README.md b/core-java-modules/core-java-lang-4/README.md
new file mode 100644
index 0000000000..ff00688772
--- /dev/null
+++ b/core-java-modules/core-java-lang-4/README.md
@@ -0,0 +1,5 @@
+## Core Java Lang (Part 4)
+
+This module contains articles about core features in the Java language
+
+- TODO
diff --git a/core-java-modules/core-java-lang-4/pom.xml b/core-java-modules/core-java-lang-4/pom.xml
new file mode 100644
index 0000000000..3e92e9f9c7
--- /dev/null
+++ b/core-java-modules/core-java-lang-4/pom.xml
@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project
+    xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-java-lang-4</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-lang-4</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <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>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <jmh.version>1.28</jmh.version>
+    </properties>
+      
+</project>
\ No newline at end of file
diff --git a/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/BenchmarkRunner.java b/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/BenchmarkRunner.java
new file mode 100644
index 0000000000..ee34114195
--- /dev/null
+++ b/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;
+    }
+
+}
diff --git a/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/ClassVariableFinal.java b/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/ClassVariableFinal.java
new file mode 100644
index 0000000000..1aeef76e58
--- /dev/null
+++ b/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/ClassVariableFinal.java
@@ -0,0 +1,19 @@
+package com.baeldung.finalkeyword;
+
+import java.io.Console;
+
+public class ClassVariableFinal {
+
+    static final boolean doX = false;
+    static final boolean doY = true;
+
+    public static void main(String[] args) {
+        Console console = System.console();
+        if (doX) {
+            console.writer().println("x");
+        } else if (doY) {
+            console.writer().println("y");
+        }
+    }
+
+}
diff --git a/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/ClassVariableNonFinal.java b/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/ClassVariableNonFinal.java
new file mode 100644
index 0000000000..a6d83a66cb
--- /dev/null
+++ b/core-java-modules/core-java-lang-4/src/main/java/com/baeldung/finalkeyword/ClassVariableNonFinal.java
@@ -0,0 +1,19 @@
+package com.baeldung.finalkeyword;
+
+import java.io.Console;
+
+public class ClassVariableNonFinal {
+
+    static boolean doX = false;
+    static boolean doY = true;
+
+    public static void main(String[] args) {
+        Console console = System.console();
+        if (doX) {
+            console.writer().println("x");
+        } else if (doY) {
+            console.writer().println("y");
+        }
+    }
+
+}
diff --git a/core-java-modules/pom.xml b/core-java-modules/pom.xml
index 2d342c4216..7dc54bd907 100644
--- a/core-java-modules/pom.xml
+++ b/core-java-modules/pom.xml
@@ -82,6 +82,7 @@
         <module>core-java-lang</module>
         <module>core-java-lang-2</module>
         <module>core-java-lang-3</module>
+        <module>core-java-lang-4</module>
         <module>core-java-lang-math</module>
         <module>core-java-lang-math-2</module>
         <module>core-java-lang-math-3</module>