diff --git a/out/artifacts/jungle_jar/jungle.jar b/out/artifacts/jungle_jar/jungle.jar
index 1566469..b375006 100644
Binary files a/out/artifacts/jungle_jar/jungle.jar and b/out/artifacts/jungle_jar/jungle.jar differ
diff --git a/src/main/java/com/jungle/ast/Node.java b/src/main/java/com/jungle/ast/Node.java
index 37643b6..cfe32d7 100644
--- a/src/main/java/com/jungle/ast/Node.java
+++ b/src/main/java/com/jungle/ast/Node.java
@@ -166,7 +166,7 @@ public String toString() {
 
   // region Save AST
   @NotNull
-  private static final FileLogger saveLog = new FileLogger("SaveAst");
+  private static final FileLogger saveLogger = new FileLogger("SaveAst");
 
   public static void save(@NotNull BufferedWriter writer, @Nullable INode node) {
     // Non-recursive traversal
@@ -174,36 +174,36 @@ public static void save(@NotNull BufferedWriter writer, @Nullable INode node) {
     nodeStack.push(node);
     while (nodeStack.size() > 0) {
       INode nextNode = nodeStack.pop();
-      saveLog.debug("---");
+      saveLogger.debug("---");
       if (nextNode == null) {
-        saveLog.debug("node is terminal");
+        saveLogger.debug("node is terminal");
         try {
           writer.write(TERMINAL);
         } catch (IOException e) {
           throw new SaveError("failed to write terminal", e);
         }
       } else {
-        saveLog.debug("type: " + nextNode.getType());
-        saveLog.debug("value: " + nextNode.getRawValue());
+        saveLogger.debug("type: " + nextNode.getType());
+        saveLogger.debug("value: " + nextNode.getRawValue());
         try {
           writer.write(nextNode.getType().name());
         } catch (IOException e) {
           String message = "failed to write node type";
-          saveLog.error(message, e);
+          saveLogger.error(message, e);
           throw new SaveError(message);
         }
         if (nextNode.isLeaf()) {
-          saveLog.debug("node is leaf");
+          saveLogger.debug("node is leaf");
           try {
             writer.write(DELIMITER_FIELD);
             writer.write(nextNode.getRawValue());
           } catch (IOException e) {
             String message = "failed to write node value";
-            saveLog.error(message, e);
+            saveLogger.error(message, e);
             throw new SaveError(message);
           }
         } else {
-          saveLog.debug("node is parent");
+          saveLogger.debug("node is parent");
           nodeStack.push(nextNode.getRight());
           nodeStack.push(nextNode.getLeft());
         }
@@ -212,7 +212,7 @@ public static void save(@NotNull BufferedWriter writer, @Nullable INode node) {
         writer.write(DELIMITER_LINE);
       } catch (IOException e) {
         String message = "failed to write line delimiter";
-        saveLog.error(message, e);
+        saveLogger.error(message, e);
         throw new SaveError(message);
       }
     }
@@ -222,7 +222,7 @@ public static void save(@NotNull BufferedWriter writer, @Nullable INode node) {
 
   // region Load AST
 
-  private static final FileLogger loadLog = new FileLogger("LoadAst");
+  private static final FileLogger loadLogger = new FileLogger("LoadAst");
 
   @Nullable
   public static INode load(@NotNull BufferedReader reader) {
@@ -235,21 +235,21 @@ public static INode load(@NotNull BufferedReader reader) {
       line = reader.readLine();
     } catch (IOException e) {
       String message = "failed to read file";
-      loadLog.error(message, e);
+      loadLogger.error(message, e);
       throw new LoadError(message);
     }
     boolean hasStreamEnded = line == null;
     if (hasStreamEnded) {
-      loadLog.warn("end of stream reached");
+      loadLogger.warn("end of stream reached");
       return null;
     }
     boolean hasEmptyLine = line.length() == 0;
     if (hasEmptyLine) {
-      loadLog.debug("line is empty");
+      loadLogger.debug("line is empty");
       return null;
     }
     if (line.trim().startsWith(Character.toString(TERMINAL))) {
-      loadLog.debug("line is terminal");
+      loadLogger.debug("line is terminal");
       return null;
     }
     int splitIndex = line.indexOf(DELIMITER_FIELD);
@@ -260,22 +260,22 @@ public static INode load(@NotNull BufferedReader reader) {
       value = null;
     } else if (splitIndex == 0) {
       String message = "line missing type";
-      loadLog.error(message);
+      loadLogger.error(message);
       throw new LoadError(message);
     } else {
       type = line.substring(0, splitIndex);
       value = line.substring(splitIndex + 1);
     }
     type = type.trim();
-    loadLog.debug("---");
-    loadLog.debug("type: " + type);
-    loadLog.debug("value: " + value);
+    loadLogger.debug("---");
+    loadLogger.debug("type: " + type);
+    loadLogger.debug("value: " + value);
     Node node;
     try {
        node = new Node(NodeType.valueOf(type));
     } catch (IllegalArgumentException e) {
       String message = "line type invalid";
-      loadLog.error(message, e);
+      loadLogger.error(message, e);
       throw new LoadError(message);
     }
     boolean isLeafNode = value != null;
diff --git a/src/main/java/com/jungle/common/ClassLoader.java b/src/main/java/com/jungle/common/ClassLoader.java
index 7e7eb66..9744ed2 100644
--- a/src/main/java/com/jungle/common/ClassLoader.java
+++ b/src/main/java/com/jungle/common/ClassLoader.java
@@ -10,8 +10,13 @@
 
 import org.jetbrains.annotations.NotNull;
 
+import com.jungle.logger.FileLogger;
+
 public class ClassLoader {
 
+    @NotNull
+    private static final FileLogger logger = new FileLogger(ClassLoader.class.getName());
+
     public static Class<?> load(@NotNull String classPaths, @NotNull String className)
         throws MalformedURLException, ClassNotFoundException
     {
@@ -42,7 +47,7 @@ public static Class<?> load(@NotNull String className)
         if (classPath == null) {
             classPath = ".";
         }
-        System.out.println(String.format("loading class from %s", classPath));
+        logger.debug(String.format("loading class from %s", classPath));
         return load(classPath, className);
     }
 }
diff --git a/src/main/java/com/jungle/compiler/Compiler.java b/src/main/java/com/jungle/compiler/Compiler.java
index 9c2f71f..778baf7 100644
--- a/src/main/java/com/jungle/compiler/Compiler.java
+++ b/src/main/java/com/jungle/compiler/Compiler.java
@@ -19,8 +19,8 @@
 import static org.objectweb.asm.Opcodes.*;
 
 public class Compiler {
-
-    public static final FileLogger log = new FileLogger(Compiler.class.getSimpleName());
+    @NotNull
+    private static final FileLogger logger = new FileLogger(Compiler.class.getSimpleName());
 
     // region Helpers
 
@@ -30,7 +30,7 @@ public static void writeClassFile(@NotNull String className, byte[] classData) {
             Files.write(classPath, classData);
         } catch (IOException e) {
             String message = "failed to write to class file";
-            log.error(message, e);
+            logger.error(message, e);
             throw new CompilerError(message);
         }
     }
@@ -41,17 +41,17 @@ public void compile(@NotNull String mainClassName, @NotNull IVisitor mainVisitor
         // TODO: handle multi-class
         if (ast == null) {
             String message = "AST is null";
-            log.error(message);
+            logger.error(message);
             throw new CompilerError(message);
         }
-        log.debug("generating entrypoint class from template");
+        logger.debug("generating entrypoint class from template");
         ClassWriter initialClassWriter = visitMainClass(mainClassName); // template
         ClassReader classReader = new ClassReader(initialClassWriter.toByteArray());
         ClassWriter classWriter = new ClassWriter(classReader, ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
         ClassVisitor entrypoint = new MainClassVisitor(classWriter, mainVisitor, ast);
-        log.debug("traversing AST");
+        logger.debug("traversing AST");
         classReader.accept(entrypoint, ClassReader.SKIP_FRAMES | ClassReader.SKIP_DEBUG);
-        log.debug("writing class file");
+        logger.debug("writing class file");
         writeClassFile(mainClassName, classWriter.toByteArray());
     }
 
@@ -60,7 +60,7 @@ public void compile(@NotNull String mainClassName, @NotNull IVisitor mainVisitor
     @NotNull
     protected ClassWriter visitMainClass(@NotNull String className) {
         // class Entrypoint extends Object {}
-        log.debug("visit main class");
+        logger.debug("visit main class");
         int flags = ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES;
         ClassWriter cw = new ClassWriter(flags);
         cw.visit(
@@ -82,7 +82,7 @@ protected ClassWriter visitMainClass(@NotNull String className) {
     @NotNull
     public static MethodVisitor visitDefaultConstructor(@NotNull ClassWriter cw) {
         // public ClassConstructor() { Object::super(); return; }
-        log.debug("visit default constructor");
+        logger.debug("visit default constructor");
         MethodVisitor mv = cw.visitMethod(
                 ACC_PUBLIC,
                 "<init>",
@@ -106,7 +106,7 @@ public static MethodVisitor visitDefaultConstructor(@NotNull ClassWriter cw) {
     @NotNull
     public static MethodVisitor visitMainMethod(@NotNull ClassWriter cw) {
         // public static void main(String[]) { return; }
-        log.debug("visit main method");
+        logger.debug("visit main method");
         MethodVisitor mv = cw.visitMethod(
                 ACC_PUBLIC + ACC_STATIC,
                 MainMethodVisitor.MAIN_METHOD_NAME,
diff --git a/src/main/java/com/jungle/compiler/MainClassVisitor.java b/src/main/java/com/jungle/compiler/MainClassVisitor.java
index b6933b7..584d81d 100644
--- a/src/main/java/com/jungle/compiler/MainClassVisitor.java
+++ b/src/main/java/com/jungle/compiler/MainClassVisitor.java
@@ -2,12 +2,17 @@
 
 import com.jungle.ast.INode;
 import com.jungle.compiler.visitor.IVisitor;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 
 public class MainClassVisitor extends ClassVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(MainClassVisitor.class.getSimpleName());
+
     @NotNull
     private final IVisitor mainVisitor;
 
@@ -25,7 +30,7 @@ public MethodVisitor visitMethod(int flags, String name, String desc, String sig
         MethodVisitor mv = super.visitMethod(flags, name, desc, signature, exceptions);
         boolean isMainMethod = MainMethodVisitor.MAIN_METHOD_NAME.equals(name);
         if (isMainMethod) {
-            Compiler.log.debug("emit custom instructions in main class");
+            logger.debug("emit custom instructions in main class");
             return new MainMethodVisitor(mv, mainVisitor, ast);
         }
         return mv;
diff --git a/src/main/java/com/jungle/compiler/MainMethodVisitor.java b/src/main/java/com/jungle/compiler/MainMethodVisitor.java
index dabeedd..b2e331c 100644
--- a/src/main/java/com/jungle/compiler/MainMethodVisitor.java
+++ b/src/main/java/com/jungle/compiler/MainMethodVisitor.java
@@ -2,11 +2,16 @@
 
 import com.jungle.ast.INode;
 import com.jungle.compiler.visitor.IVisitor;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 
 public class MainMethodVisitor extends MethodVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(MainMethodVisitor.class.getSimpleName());
+
     public static final String MAIN_METHOD_NAME = "main";
 
     @NotNull
@@ -24,7 +29,7 @@ public MainMethodVisitor(MethodVisitor mv, @NotNull IVisitor mainVisitor, @NotNu
     @Override
     public void visitInsn(final int opcode) {
         if (opcode == Opcodes.RETURN) {
-            Compiler.log.debug("emit instructions just before existing RETURN operation");
+            logger.debug("emit instructions just before existing RETURN operation");
             mainVisitor.visit(this, ast);
         }
         super.visitInsn(opcode);
diff --git a/src/main/java/com/jungle/compiler/operand/OperandStackContext.java b/src/main/java/com/jungle/compiler/operand/OperandStackContext.java
index 2f4ca33..d980108 100644
--- a/src/main/java/com/jungle/compiler/operand/OperandStackContext.java
+++ b/src/main/java/com/jungle/compiler/operand/OperandStackContext.java
@@ -3,6 +3,8 @@
 import com.jungle.compiler.symbol.SymbolEntry;
 import com.jungle.compiler.symbol.SymbolTable;
 import com.jungle.compiler.symbol.SymbolType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
@@ -10,6 +12,9 @@
 import java.util.Stack;
 
 public class OperandStackContext {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(OperandStackContext.class.getName());
+
     // region Singleton Factory
     @Nullable
     private static OperandStackContext operandStackContext = null;
@@ -60,7 +65,7 @@ public void visitLoad(
             @NotNull String variableName
     ) {
         // Get local variable index value and push variable value onto the operand stack
-        System.out.println("visit load " + variableName);
+        logger.debug("visit load " + variableName);
 
         SymbolEntry entry = getSymbolTable().get(variableName);
         if (entry == null) {
@@ -84,7 +89,7 @@ public void visitStore(
             @NotNull String variableName
     ) {
         // Pop value off the operand stack and set local variable index value
-        System.out.println("visit store " + variableName);
+        logger.debug("visit store " + variableName);
 
         OperandStackType variableType = pop();
         SymbolType variableSymbolType = variableType.getSymbolType();
diff --git a/src/main/java/com/jungle/compiler/visitor/AssertVisitor.java b/src/main/java/com/jungle/compiler/visitor/AssertVisitor.java
index a4f2511..723ae5c 100644
--- a/src/main/java/com/jungle/compiler/visitor/AssertVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/AssertVisitor.java
@@ -4,6 +4,8 @@
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
 import com.jungle.compiler.operand.OperandStackType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.Label;
@@ -11,6 +13,13 @@
 import org.objectweb.asm.Opcodes;
 
 public class AssertVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(AssertVisitor.class.getName());
+
+    /* TODO
+     * It might be possible to use reflection to provide more context on the assertion.
+     * For example: which method, which line, which variables, etc.
+     */
     @Nullable
     private OperandStackContext operandStackContext;
 
@@ -52,7 +61,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit assert " + ast);
+        logger.debug("visit assert " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected assert");
diff --git a/src/main/java/com/jungle/compiler/visitor/AssignmentVisitor.java b/src/main/java/com/jungle/compiler/visitor/AssignmentVisitor.java
index 7643d87..03c090a 100644
--- a/src/main/java/com/jungle/compiler/visitor/AssignmentVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/AssignmentVisitor.java
@@ -3,11 +3,16 @@
 import com.jungle.ast.INode;
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 
 public class AssignmentVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(AssignmentVisitor.class.getName());
+
     @Nullable
     private OperandStackContext operandStackContext;
 
@@ -49,7 +54,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit assignment " + ast);
+        logger.debug("visit assignment " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected assignment");
diff --git a/src/main/java/com/jungle/compiler/visitor/BlockVisitor.java b/src/main/java/com/jungle/compiler/visitor/BlockVisitor.java
index 305de72..6a36f34 100644
--- a/src/main/java/com/jungle/compiler/visitor/BlockVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/BlockVisitor.java
@@ -2,11 +2,16 @@
 
 import com.jungle.ast.INode;
 import com.jungle.ast.NodeType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 
 public class BlockVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(BlockVisitor.class.getName());
+
     @Nullable
     private MainVisitor mainVisitor;
 
@@ -33,7 +38,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit block " + ast);
+        logger.debug("visit block " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected block");
diff --git a/src/main/java/com/jungle/compiler/visitor/BooleanOperatorVisitor.java b/src/main/java/com/jungle/compiler/visitor/BooleanOperatorVisitor.java
index 2c6eaaf..f65c23b 100644
--- a/src/main/java/com/jungle/compiler/visitor/BooleanOperatorVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/BooleanOperatorVisitor.java
@@ -3,6 +3,8 @@
 import com.jungle.ast.INode;
 import com.jungle.ast.Node;
 import com.jungle.ast.NodeType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
@@ -12,6 +14,9 @@
 import java.util.Set;
 
 public class BooleanOperatorVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(BooleanOperatorVisitor.class.getName());
+
     @NotNull
     private static final INode PUSH_TRUE_NODE = new Node(NodeType.LITERAL_INTEGER).withRawValue("1");
 
@@ -58,7 +63,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit boolean operator " + ast);
+        logger.debug("visit boolean operator " + ast);
 
         // Optimization idea:
         //  if the left expression has a shorter depth (fewer operations) than the right,
diff --git a/src/main/java/com/jungle/compiler/visitor/CastIntegerVisitor.java b/src/main/java/com/jungle/compiler/visitor/CastIntegerVisitor.java
index 319c5f4..49c8c4d 100644
--- a/src/main/java/com/jungle/compiler/visitor/CastIntegerVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/CastIntegerVisitor.java
@@ -4,12 +4,17 @@
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
 import com.jungle.compiler.operand.OperandStackType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 
 public class CastIntegerVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(CastIntegerVisitor.class.getName());
+
     @Nullable
     private OperandStackContext operandStackContext;
 
@@ -51,7 +56,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit cast integer " + ast);
+        logger.debug("visit cast integer " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected cast integer");
@@ -65,7 +70,7 @@ public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
         OperandStackType type = getOperandStackContext().pop();
         switch (type) {
             case INTEGER: {
-                System.out.println("WARN: value is already an integer");
+                logger.warn("value is already an integer");
             } break;
             case FLOAT: {
                 mv.visitInsn(Opcodes.F2I);
diff --git a/src/main/java/com/jungle/compiler/visitor/ExpressionVisitor.java b/src/main/java/com/jungle/compiler/visitor/ExpressionVisitor.java
index dd44ed7..ae6adfc 100644
--- a/src/main/java/com/jungle/compiler/visitor/ExpressionVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/ExpressionVisitor.java
@@ -1,11 +1,16 @@
 package com.jungle.compiler.visitor;
 
 import com.jungle.ast.INode;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 
 public class ExpressionVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(ExpressionVisitor.class.getName());
+
     @Nullable
     private IdentifierVisitor identifierVisitor;
 
@@ -86,7 +91,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit expression " + ast);
+        logger.debug("visit expression " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected expression");
diff --git a/src/main/java/com/jungle/compiler/visitor/IdentifierVisitor.java b/src/main/java/com/jungle/compiler/visitor/IdentifierVisitor.java
index 236bcb4..14b1656 100644
--- a/src/main/java/com/jungle/compiler/visitor/IdentifierVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/IdentifierVisitor.java
@@ -3,11 +3,16 @@
 import com.jungle.ast.INode;
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 
 public class IdentifierVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(IdentifierVisitor.class.getName());
+
     @Nullable
     private OperandStackContext operandStackContext;
 
@@ -35,7 +40,7 @@ public boolean canVisit(@NotNull INode node) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit identifier " + ast);
+        logger.debug("visit identifier " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected identifier");
diff --git a/src/main/java/com/jungle/compiler/visitor/IfVisitor.java b/src/main/java/com/jungle/compiler/visitor/IfVisitor.java
index 3ef0f47..bb10cfd 100644
--- a/src/main/java/com/jungle/compiler/visitor/IfVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/IfVisitor.java
@@ -5,6 +5,8 @@
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
 import com.jungle.compiler.operand.OperandStackType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.Label;
@@ -12,6 +14,9 @@
 import org.objectweb.asm.Opcodes;
 
 public class IfVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(IfVisitor.class.getName());
+
     @Nullable
     private OperandStackContext operandStackContext;
 
@@ -70,7 +75,7 @@ public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
     }
 
     protected void visit(@NotNull MethodVisitor mv, @NotNull CompareTo compareTo, @NotNull INode ast) {
-        System.out.println("visit if " + ast);
+        logger.debug("visit if " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected if");
diff --git a/src/main/java/com/jungle/compiler/visitor/LiteralVisitor.java b/src/main/java/com/jungle/compiler/visitor/LiteralVisitor.java
index 7fd64f6..d2a0787 100644
--- a/src/main/java/com/jungle/compiler/visitor/LiteralVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/LiteralVisitor.java
@@ -4,6 +4,8 @@
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
 import com.jungle.compiler.operand.OperandStackType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
@@ -15,6 +17,9 @@
 import static com.jungle.ast.NodeType.*;
 
 public class LiteralVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(LiteralVisitor.class.getName());
+
     private static final Set<NodeType> LITERALS = new HashSet<>(Arrays.asList(
             LITERAL_BOOLEAN,
             LITERAL_CHARACTER,
@@ -49,7 +54,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit literal " + ast);
+        logger.debug("visit literal " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected literal");
diff --git a/src/main/java/com/jungle/compiler/visitor/LoopVisitor.java b/src/main/java/com/jungle/compiler/visitor/LoopVisitor.java
index f55b0ef..6d28855 100644
--- a/src/main/java/com/jungle/compiler/visitor/LoopVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/LoopVisitor.java
@@ -4,6 +4,8 @@
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
 import com.jungle.compiler.operand.OperandStackType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.Label;
@@ -11,6 +13,9 @@
 import org.objectweb.asm.Opcodes;
 
 public class LoopVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(LoopVisitor.class.getName());
+
     @Nullable
     private OperandStackContext operandStackContext;
 
@@ -70,7 +75,7 @@ public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
                GOTO #loop
          end:  ...
          */
-        System.out.println("visit loop " + ast);
+        logger.debug("visit loop " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected loop");
diff --git a/src/main/java/com/jungle/compiler/visitor/MainVisitor.java b/src/main/java/com/jungle/compiler/visitor/MainVisitor.java
index d153c26..5849e9a 100644
--- a/src/main/java/com/jungle/compiler/visitor/MainVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/MainVisitor.java
@@ -1,11 +1,17 @@
 package com.jungle.compiler.visitor;
 
 import com.jungle.ast.INode;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 
 public class MainVisitor implements IVisitor {
+
+    @NotNull
+    private static final FileLogger logger = new FileLogger(MainVisitor.class.getSimpleName());
+
     @Nullable
     private LiteralVisitor literalVisitor;
 
@@ -138,7 +144,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit main " + ast);
+        logger.debug("visit main " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected main");
diff --git a/src/main/java/com/jungle/compiler/visitor/NumericOperatorVisitor.java b/src/main/java/com/jungle/compiler/visitor/NumericOperatorVisitor.java
index 3bd71be..e4c90cb 100644
--- a/src/main/java/com/jungle/compiler/visitor/NumericOperatorVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/NumericOperatorVisitor.java
@@ -5,6 +5,8 @@
 import com.jungle.compiler.operand.OperandStackContext;
 import com.jungle.compiler.operand.OperandStackType;
 import com.jungle.compiler.symbol.SymbolType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
@@ -17,6 +19,9 @@
 import static com.jungle.ast.NodeType.*;
 
 public class NumericOperatorVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(NumericOperatorVisitor.class.getName());
+
     private static final Set<NodeType> NUMERIC_OPERATORS = new HashSet<>(Arrays.asList(
             OPERATOR_ADD,
             OPERATOR_SUBTRACT,
@@ -66,7 +71,7 @@ public boolean canVisit(@NotNull INode node) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit binary operator " + ast);
+        logger.debug("visit binary operator " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected numeric operator");
diff --git a/src/main/java/com/jungle/compiler/visitor/PrintVisitor.java b/src/main/java/com/jungle/compiler/visitor/PrintVisitor.java
index 9bcf62a..93b568a 100644
--- a/src/main/java/com/jungle/compiler/visitor/PrintVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/PrintVisitor.java
@@ -4,6 +4,8 @@
 import com.jungle.ast.NodeType;
 import com.jungle.compiler.operand.OperandStackContext;
 import com.jungle.compiler.operand.OperandStackType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
@@ -11,6 +13,9 @@
 import static org.objectweb.asm.Opcodes.*;
 
 public class PrintVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(NumericOperatorVisitor.class.getName());
+
     @Nullable
     private OperandStackContext operandStackContext;
 
@@ -52,7 +57,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit print " + ast);
+        logger.debug("visit print " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected print");
diff --git a/src/main/java/com/jungle/compiler/visitor/SequenceVisitor.java b/src/main/java/com/jungle/compiler/visitor/SequenceVisitor.java
index 13804b5..c5275c9 100644
--- a/src/main/java/com/jungle/compiler/visitor/SequenceVisitor.java
+++ b/src/main/java/com/jungle/compiler/visitor/SequenceVisitor.java
@@ -2,11 +2,16 @@
 
 import com.jungle.ast.INode;
 import com.jungle.ast.NodeType;
+import com.jungle.logger.FileLogger;
+
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.objectweb.asm.MethodVisitor;
 
 public class SequenceVisitor implements IVisitor {
+    @NotNull
+    private static final FileLogger logger = new FileLogger(SequenceVisitor.class.getSimpleName());
+
     @Nullable
     private MainVisitor mainVisitor;
 
@@ -33,7 +38,7 @@ public boolean canVisit(@NotNull INode ast) {
 
     @Override
     public void visit(@NotNull MethodVisitor mv, @NotNull INode ast) {
-        System.out.println("visit sequence " + ast);
+        logger.debug("visit sequence " + ast);
 
         if (!canVisit(ast)) {
             throw new Error("expected sequence");
diff --git a/src/main/java/com/jungle/logger/AbstractLogger.java b/src/main/java/com/jungle/logger/AbstractLogger.java
index 09d9c36..e2bf93f 100644
--- a/src/main/java/com/jungle/logger/AbstractLogger.java
+++ b/src/main/java/com/jungle/logger/AbstractLogger.java
@@ -7,7 +7,7 @@
 
 public abstract class AbstractLogger implements ILogger {
     @NotNull
-    public static final LogLevel DEFAULT_LOG_LEVEL = LogLevel.INFO;
+    public static final LogLevel DEFAULT_LOG_LEVEL = LogLevel.WARN;
 
     @NotNull
     public static LogLevel getLogLevel() {
@@ -16,7 +16,7 @@ public static LogLevel getLogLevel() {
             return DEFAULT_LOG_LEVEL;
         }
         try {
-            return LogLevel.valueOf(logLevelString);
+            return LogLevel.valueOf(logLevelString.toUpperCase());
         } catch (IllegalArgumentException e) {
             return DEFAULT_LOG_LEVEL;
         }