diff --git a/src/main/java/parser/ASTBuilder.java b/src/main/java/parser/ASTBuilder.java
new file mode 100644
index 0000000..ccf3ba7
--- /dev/null
+++ b/src/main/java/parser/ASTBuilder.java
@@ -0,0 +1,20 @@
+package parser;
+
+import parser.generated.SimpleJavaBaseVisitor;
+import parser.generated.SimpleJavaParser;
+
+public class ASTBuilder extends SimpleJavaBaseVisitor<ASTNode> {
+    @Override
+    public ASTNode visitProgram(SimpleJavaParser.ProgramContext ctx) {
+        ProgramNode program = new ProgramNode();
+        for (SimpleJavaParser.ClassDeclarationContext classDeclCtx : ctx.classDeclaration()) {
+            program.addClass((ClassDeclarationNode) visit(classDeclCtx));
+        }
+        return program;
+    }
+
+    @Override
+    public ASTNode visitClassDeclaration(SimpleJavaParser.ClassDeclarationContext ctx) {
+        return new ClassDeclarationNode(ctx.IDENTIFIER().getText());
+    }
+}
diff --git a/src/main/java/parser/ASTNode.java b/src/main/java/parser/ASTNode.java
new file mode 100644
index 0000000..fad3ac0
--- /dev/null
+++ b/src/main/java/parser/ASTNode.java
@@ -0,0 +1,8 @@
+package parser;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class ASTNode { }
+
+
diff --git a/src/main/java/parser/ClassDeclarationNode.java b/src/main/java/parser/ClassDeclarationNode.java
new file mode 100644
index 0000000..e6798fa
--- /dev/null
+++ b/src/main/java/parser/ClassDeclarationNode.java
@@ -0,0 +1,11 @@
+package parser;
+
+import parser.ASTNode;
+
+public class ClassDeclarationNode extends ASTNode {
+    public String identifier;
+
+    public ClassDeclarationNode(String identifier) {
+        this.identifier = identifier;
+    }
+}
diff --git a/src/main/java/parser/Main.java b/src/main/java/parser/Main.java
new file mode 100644
index 0000000..ca8554f
--- /dev/null
+++ b/src/main/java/parser/Main.java
@@ -0,0 +1,27 @@
+package parser;
+
+import org.antlr.v4.runtime.CharStream;
+import org.antlr.v4.runtime.CharStreams;
+import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.tree.ParseTree;
+import parser.generated.SimpleJavaLexer;
+import parser.generated.SimpleJavaParser;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        // Assuming args[0] contains the path to the input file
+        CharStream codeCharStream = CharStreams.fromString("class Test { }");
+        SimpleJavaLexer lexer = new SimpleJavaLexer(codeCharStream);
+        CommonTokenStream tokens = new CommonTokenStream(lexer);
+        SimpleJavaParser parser = new SimpleJavaParser(tokens);
+
+        ParseTree tree = parser.program(); // parse the input
+
+        ASTBuilder builder = new ASTBuilder();
+        ProgramNode ast = (ProgramNode) builder.visit(tree); // build the AST
+
+        // Optionally print or process the AST
+        System.out.println("Parsed " + ast.classes.size() + " classes.");
+        System.out.println(ast.classes.get(0).identifier);
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/parser/ProgramNode.java b/src/main/java/parser/ProgramNode.java
new file mode 100644
index 0000000..2b54468
--- /dev/null
+++ b/src/main/java/parser/ProgramNode.java
@@ -0,0 +1,15 @@
+package parser;
+
+import parser.ASTNode;
+import parser.ClassDeclarationNode;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ProgramNode extends ASTNode {
+    public List<ClassDeclarationNode> classes = new ArrayList<>();
+
+    public void addClass(ClassDeclarationNode classNode) {
+        classes.add(classNode);
+    }
+}
diff --git a/src/main/java/parser/Test.txt b/src/main/java/parser/Test.txt
new file mode 100644
index 0000000..5a0c977
--- /dev/null
+++ b/src/main/java/parser/Test.txt
@@ -0,0 +1 @@
+class Test { }
\ No newline at end of file