diff --git a/pga-lib/src/main/java/com/guardsquare/proguard/assembler/AssemblyConstants.java b/pga-lib/src/main/java/com/guardsquare/proguard/assembler/AssemblyConstants.java
index 73b34e3..026becb 100644
--- a/pga-lib/src/main/java/com/guardsquare/proguard/assembler/AssemblyConstants.java
+++ b/pga-lib/src/main/java/com/guardsquare/proguard/assembler/AssemblyConstants.java
@@ -36,14 +36,14 @@ public final class AssemblyConstants
 
     public static final String ACC_ANNOTATION = "annotation";
 
-    public static final String TYPE_STRING        = "String";
-    public static final String TYPE_CLASS         = "Class";
-    public static final String TYPE_METHOD_HANDLE = "MethodHandle";
-    public static final String TYPE_METHOD_TYPE   = "MethodType";
+    public static final String TYPE_STRING        = "java.lang.String";
+    public static final String TYPE_CLASS         = "java.lang.Class";
+    public static final String TYPE_METHOD_HANDLE = "java.lang.invoke.MethodHandle";
+    public static final String TYPE_METHOD_TYPE   = "java.lang.invoke.MethodType";
     public static final String TYPE_DYNAMIC       = "Dynamic";
-    public static final String TYPE_ANNOTATION    = "Annotation";
-    public static final String TYPE_ENUM          = "Enum";
-    public static final String TYPE_ARRAY         = "Array";
+    public static final String TYPE_ANNOTATION    = "java.lang.Annotation";
+    public static final String TYPE_ENUM          = "java.lang.Enum";
+    public static final String TYPE_ARRAY         = "java.lang.reflect.Array";
     public static final String TYPE_DOUBLE        = "D";
     public static final String TYPE_FLOAT         = "F";
     public static final String TYPE_LONG          = "L";
diff --git a/pga-lib/src/test/kotlin/com/guardsquare/proguard/AssembleDisassembleTest.kt b/pga-lib/src/test/kotlin/com/guardsquare/proguard/AssembleDisassembleTest.kt
new file mode 100644
index 0000000..af1b176
--- /dev/null
+++ b/pga-lib/src/test/kotlin/com/guardsquare/proguard/AssembleDisassembleTest.kt
@@ -0,0 +1,29 @@
+package com.guardsquare.proguard
+
+import io.kotest.core.spec.style.FreeSpec
+import proguard.testutils.ClassPoolBuilder
+import proguard.testutils.JavaSource
+
+class AssembleDisassembleTest : FreeSpec({
+    "Test TYPE_METHOD_TYPE constant" {
+        val classBPools = ClassPoolBuilder.fromSource(
+            JavaSource(
+                "Main.java",
+                """
+                import java.util.function.Consumer;                    
+                
+                public class Main {
+                    public static void test(Consumer<String> lambda) {
+                        lambda.accept("Hello world!");
+                    }
+                    
+                    public static void main(String[] args) {
+                        test(System.out::println);
+                    }
+                }
+            """.trimIndent())
+        )
+
+        buildProgramClass(disassembleClass(classBPools.programClassPool.getClass("Main")))
+    }
+})
diff --git a/pga-lib/src/test/kotlin/com/guardsquare/proguard/AssemblerErrorsTest.kt b/pga-lib/src/test/kotlin/com/guardsquare/proguard/AssemblerErrorsTest.kt
index 41a7168..1987d0e 100644
--- a/pga-lib/src/test/kotlin/com/guardsquare/proguard/AssemblerErrorsTest.kt
+++ b/pga-lib/src/test/kotlin/com/guardsquare/proguard/AssemblerErrorsTest.kt
@@ -114,17 +114,3 @@ class AssemblerErrorsTest : FreeSpec({
         }
     }
 })
-
-/**
- * Helper function to build and parse a java bytecode class from a string
- */
-fun buildProgramClass(jbc: String) {
-    val programClass = ProgramClass()
-    programClass.accept(
-        ClassParser(
-            Parser(
-                StringReader(jbc),
-            ),
-        ),
-    )
-}
diff --git a/pga-lib/src/test/kotlin/com/guardsquare/proguard/TestUtils.kt b/pga-lib/src/test/kotlin/com/guardsquare/proguard/TestUtils.kt
new file mode 100644
index 0000000..295318b
--- /dev/null
+++ b/pga-lib/src/test/kotlin/com/guardsquare/proguard/TestUtils.kt
@@ -0,0 +1,38 @@
+package com.guardsquare.proguard
+
+import com.guardsquare.proguard.assembler.ClassParser
+import com.guardsquare.proguard.assembler.Parser
+import com.guardsquare.proguard.disassembler.ClassPrinter
+import com.guardsquare.proguard.disassembler.Printer
+import proguard.classfile.Clazz
+import proguard.classfile.ProgramClass
+import java.io.StringReader
+import java.io.StringWriter
+
+/**
+ * Helper function to build and parse a java bytecode class from a string
+ */
+fun buildProgramClass(jbc: String) {
+    val programClass = ProgramClass()
+    programClass.accept(
+        ClassParser(
+            Parser(
+                StringReader(jbc),
+            ),
+        ),
+    )
+}
+
+/**
+ * Helper function to disassemble a [Clazz] object.
+ */
+fun disassembleClass(clazz: Clazz): String {
+    val writer = StringWriter()
+        clazz.accept(
+            ClassPrinter(
+            Printer(writer)
+        )
+    )
+
+    return writer.toString();
+}