diff --git a/pom.xml b/pom.xml
index 2f8383a..d84bb2c 100755
--- a/pom.xml
+++ b/pom.xml
@@ -25,11 +25,6 @@
 		<slf4j.version>1.7.28</slf4j.version>
 	</properties>
 	<dependencies>
-		<dependency>
-			<groupId>commons-lang</groupId>
-			<artifactId>commons-lang</artifactId>
-			<version>2.6</version>
-		</dependency>
 		<dependency>
 			<groupId>org.antlr</groupId>
 			<artifactId>antlr4</artifactId>
diff --git a/src/main/java/io/proleap/vb6/asg/metamodel/impl/ScopedElementImpl.java b/src/main/java/io/proleap/vb6/asg/metamodel/impl/ScopedElementImpl.java
index a107d58..e63ed3e 100755
--- a/src/main/java/io/proleap/vb6/asg/metamodel/impl/ScopedElementImpl.java
+++ b/src/main/java/io/proleap/vb6/asg/metamodel/impl/ScopedElementImpl.java
@@ -9,7 +9,6 @@
 package io.proleap.vb6.asg.metamodel.impl;
 
 import org.antlr.v4.runtime.ParserRuleContext;
-import org.apache.commons.lang.StringUtils;
 
 import io.proleap.vb6.asg.metamodel.Module;
 import io.proleap.vb6.asg.metamodel.Program;
@@ -59,6 +58,6 @@ public abstract class ScopedElementImpl extends ASGElementImpl implements Scoped
 	}
 
 	protected String getSymbol(final String name) {
-		return StringUtils.isEmpty(name) ? name : name.toLowerCase();
+		return name == null || name.isEmpty() ? name : name.toLowerCase();
 	}
 }
diff --git a/src/test/java/io/proleap/vb6/TestGenerator.java b/src/test/java/io/proleap/vb6/TestGenerator.java
index d8aba88..8935746 100755
--- a/src/test/java/io/proleap/vb6/TestGenerator.java
+++ b/src/test/java/io/proleap/vb6/TestGenerator.java
@@ -18,7 +18,6 @@ import java.util.Arrays;
 
 import org.antlr.v4.runtime.CharStreams;
 import org.antlr.v4.runtime.CommonTokenStream;
-import org.apache.commons.lang.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -110,7 +109,8 @@ public class TestGenerator {
 						subOutputDirectory.mkdirs();
 
 						// determine the package name of test classes
-						final String subPackageName = StringUtils.isEmpty(packageName) ? subInputDirectoryName
+						final String subPackageName = packageName == null || packageName.isEmpty()
+								? subInputDirectoryName
 								: packageName + "." + subInputDirectoryName;
 
 						generateTestClasses(subInputDirectory, subOutputDirectory, subPackageName);
diff --git a/src/test/java/io/proleap/vb6/runner/impl/VbParseTestRunnerImpl.java b/src/test/java/io/proleap/vb6/runner/impl/VbParseTestRunnerImpl.java
index 86dd965..40603a9 100644
--- a/src/test/java/io/proleap/vb6/runner/impl/VbParseTestRunnerImpl.java
+++ b/src/test/java/io/proleap/vb6/runner/impl/VbParseTestRunnerImpl.java
@@ -21,7 +21,6 @@ import java.nio.file.Files;
 import org.antlr.v4.runtime.CharStreams;
 import org.antlr.v4.runtime.CommonTokenStream;
 import org.antlr.v4.runtime.tree.Trees;
-import org.apache.commons.lang.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -58,7 +57,7 @@ public class VbParseTestRunnerImpl implements VbParseTestRunner {
 
 		final String treeFileData = Files.readString(treeFile.toPath(), StandardCharsets.UTF_8);
 
-		if (!StringUtils.isEmpty(treeFileData)) {
+		if (treeFileData != null && !treeFileData.isEmpty()) {
 			LOG.info("Comparing parse tree with file {}.", treeFile.getName());
 
 			final String inputFileTree = Trees.toStringTree(startRule, parser);
diff --git a/src/test/java/io/proleap/vb6/util/TreeUtils.java b/src/test/java/io/proleap/vb6/util/TreeUtils.java
index e018c2a..c9e3a84 100644
--- a/src/test/java/io/proleap/vb6/util/TreeUtils.java
+++ b/src/test/java/io/proleap/vb6/util/TreeUtils.java
@@ -7,7 +7,6 @@ import org.antlr.v4.runtime.Parser;
 import org.antlr.v4.runtime.misc.Utils;
 import org.antlr.v4.runtime.tree.Tree;
 import org.antlr.v4.runtime.tree.Trees;
-import org.apache.commons.lang.StringUtils;
 
 public class TreeUtils {
 
@@ -16,7 +15,7 @@ public class TreeUtils {
 	public static final String TAB = "\t";
 
 	public static String indent(final int indent) {
-		return StringUtils.repeat(TAB, indent);
+		return TAB.repeat(indent);
 	}
 
 	/**