diff --git a/src/main/java/perfix/MethodInvocation.java b/src/main/java/perfix/MethodInvocation.java
index 7b519af..92e4588 100644
--- a/src/main/java/perfix/MethodInvocation.java
+++ b/src/main/java/perfix/MethodInvocation.java
@@ -4,25 +4,19 @@ package perfix;
  * contains start and stop time for method/query/servlet
  */
 public class MethodInvocation {
-    private final long t0;
-    private final String name;
-    long t1;
+    private final long timestamp;
+    long duration;
 
     MethodInvocation(String name) {
-        t0 = System.nanoTime();
-        if (name != null) {
-            this.name = name;
-        } else {
-            this.name = "<error occurred>";
-        }
+        timestamp = System.nanoTime();
+
     }
 
-    String getName() {
-        return name;
+    public long getDuration() {
+        return duration;
     }
 
-    long getDuration() {
-        return t1 - t0;
+    public void registerEndingTime(long t1) {
+        duration = t1 - timestamp;
     }
-
 }
diff --git a/src/main/java/perfix/MethodNode.java b/src/main/java/perfix/MethodNode.java
index ff70e57..5be85f6 100644
--- a/src/main/java/perfix/MethodNode.java
+++ b/src/main/java/perfix/MethodNode.java
@@ -8,14 +8,14 @@ public class MethodNode {
     public final String name;
     public final List<MethodNode> children;
     public MethodNode parent;
-    public Report report;
+    private MethodInvocation invocation;
 
     public MethodNode(String name) {
         this.name = name;
         this.children = new ArrayList<>();
     }
 
-    public void addChild(MethodNode child){
+    public void addChild(MethodNode child) {
         children.add(child);
     }
 
@@ -23,10 +23,6 @@ public class MethodNode {
         return name;
     }
 
-    public Report getReport() {
-        return report;
-    }
-
     public List<MethodNode> getChildren() {
         return children;
     }
@@ -51,5 +47,11 @@ public class MethodNode {
         return Objects.hash(name);
     }
 
+    public MethodInvocation getInvocation() {
+        return invocation;
+    }
 
+    public void setInvocation(MethodInvocation invocation) {
+        this.invocation = invocation;
+    }
 }
diff --git a/src/main/java/perfix/Registry.java b/src/main/java/perfix/Registry.java
index 21b7c41..b074ea0 100644
--- a/src/main/java/perfix/Registry.java
+++ b/src/main/java/perfix/Registry.java
@@ -5,11 +5,9 @@ import perfix.instrument.Util;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentSkipListMap;
-import java.util.concurrent.atomic.LongAdder;
 
 public class Registry {
 
-    private static final Map<String, List<MethodInvocation>> methods = new ConcurrentHashMap<>();
     private static final List<MethodNode> callstack = new ArrayList<>();
     private static final ThreadLocal<MethodNode> currentMethod = new ThreadLocal<>();
 
@@ -26,7 +24,7 @@ public class Registry {
     @SuppressWarnings("unused")
     public static MethodInvocation start(String name) {
         MethodInvocation methodInvocation = new MethodInvocation(name);
-        MethodNode newNode = new MethodNode(methodInvocation.getName());
+        MethodNode newNode = new MethodNode(name);
 
         MethodNode parent = currentMethod.get();
         if (parent != null) {
@@ -52,44 +50,43 @@ public class Registry {
     @SuppressWarnings("unused")
     public static void stop(MethodInvocation methodInvocation) {
         if (methodInvocation != null) {
-            methodInvocation.t1 = System.nanoTime();
-            methods.computeIfAbsent(methodInvocation.getName(), key -> new ArrayList<>()).add(methodInvocation);
+            methodInvocation.registerEndingTime(System.nanoTime());
         }
         MethodNode methodNode = currentMethod.get();
-        if (methodNode != null) {
-            currentMethod.set(methodNode.parent);
-        }
+        methodNode.setInvocation(methodInvocation);
+
+        currentMethod.set(methodNode.parent);
     }
 
     public static SortedMap<Long, Report> sortedMethodsByDuration() {
+        //walk the stack to group methods by their name
+        Map<String, List<MethodInvocation>> methods = new ConcurrentHashMap<>();
+        collectInvocationsPerMethodName(methods, callstack);
+
+        //gather invocations by method name and calculate statistics
         SortedMap<Long, Report> sortedByTotal = new ConcurrentSkipListMap<>(Comparator.reverseOrder());
         methods.forEach((name, measurements) -> {
-            LongAdder totalDuration = new LongAdder();
-            measurements.stream()
+            long totalDuration = measurements.stream()
                     .filter(Objects::nonNull)
-                    .forEach(m -> totalDuration.add(m.getDuration()));
-            sortedByTotal.put(totalDuration.longValue(), new Report(name, measurements.size(), totalDuration.longValue()));
+                    .mapToLong(MethodInvocation::getDuration).sum();
+            sortedByTotal.put(totalDuration, new Report(name, measurements.size(), totalDuration));
         });
         return sortedByTotal;
     }
 
+    private static void collectInvocationsPerMethodName(Map<String, List<MethodInvocation>> invocations, List<MethodNode> nodes) {
+        nodes.forEach(methodNode -> {
+            invocations.computeIfAbsent(methodNode.getName(), key -> new ArrayList<>()).add(methodNode.getInvocation());
+            collectInvocationsPerMethodName(invocations, methodNode.children);
+        });
+
+    }
+
     public static List<MethodNode> getCallStack() {
-        addReport(callstack);
         return callstack;
     }
 
-    private static void addReport(List<MethodNode> callstack) {
-        callstack.forEach(methodNode -> {
-            LongAdder totalDuration = new LongAdder();
-            List<MethodInvocation> methodInvocations = methods.get(methodNode.name);
-            methodInvocations.forEach(methodInvocation -> totalDuration.add(methodInvocation.getDuration()));
-            methodNode.report = new Report(methodNode.name, methodInvocations.size(), totalDuration.longValue());
-            addReport(methodNode.children);
-        });
-    }
-
     public static void clear() {
-        methods.clear();
         callstack.clear();
     }
 }
diff --git a/src/main/java/perfix/server/json/SynthSerializerFactory.java b/src/main/java/perfix/server/json/SynthSerializerFactory.java
index 3a8c4ad..880acbf 100644
--- a/src/main/java/perfix/server/json/SynthSerializerFactory.java
+++ b/src/main/java/perfix/server/json/SynthSerializerFactory.java
@@ -102,7 +102,7 @@ public class SynthSerializerFactory implements SerializerFactory {
     /*
      * Creates the source, handling the for JSON different types of classes
      */
-    private <T> String createToJSONStringMethodSource(CtClass beanClass) throws NotFoundException {
+    private String createToJSONStringMethodSource(CtClass beanClass) throws NotFoundException {
         String source = "public String handle(Object object){\n";
         if (beanClass.isArray()) {
             source += "\tObject[] array=(Object[])object;\n";
@@ -191,14 +191,10 @@ public class SynthSerializerFactory implements SerializerFactory {
     }
 
     private boolean isCollection(CtClass beanClass) throws NotFoundException {
-        List<CtClass> interfaces = new ArrayList<CtClass>(asList(beanClass.getInterfaces()));
+        List<CtClass> interfaces = new ArrayList<>(asList(beanClass.getInterfaces()));
         interfaces.add(beanClass);
-        for (CtClass interfaze : interfaces) {
-            if (interfaze.getName().equals(COLLECTION) || interfaze.getName().equals(LIST) || interfaze.getName().equals(SET)) {
-                return true;
-            }
-        }
-        return false;
+        boolean is = interfaces.stream().anyMatch(interfaze -> interfaze.getName().equals(COLLECTION) || interfaze.getName().equals(LIST) || interfaze.getName().equals(SET));
+        return is;
     }
 
     private boolean isMap(CtClass beanClass) throws NotFoundException {
@@ -212,7 +208,7 @@ public class SynthSerializerFactory implements SerializerFactory {
      */
     private String addPair(CtClass classToSerialize, String source, CtMethod getter) throws NotFoundException {
         source += jsonKey(getter);
-        source += ": "; // what is the rule when it comes to spaces in json?
+        source += ":";
         source += jsonValue(classToSerialize, getter);
         return source;
     }
diff --git a/src/testapp/java/testperfix/cmdline/App.java b/src/testapp/java/testperfix/cmdline/App.java
index c604911..7c9900b 100644
--- a/src/testapp/java/testperfix/cmdline/App.java
+++ b/src/testapp/java/testperfix/cmdline/App.java
@@ -22,7 +22,7 @@ public class App {
         try {
             someJdbcStatementMethod();
             someJdbcPreparedStatementMethod();
-            someOtherMethod();
+            someOtherMethod(0);
             TimeUnit.SECONDS.sleep(1);
         } catch (Exception e) {
             e.printStackTrace();
@@ -31,7 +31,7 @@ public class App {
 
     private static void someJdbcStatementMethod() {
         try {
-            BasicDataSource dataSource=new BasicDataSource();
+            BasicDataSource dataSource = new BasicDataSource();
             dataSource.setDriverClassName("org.h2.Driver");
             dataSource.setUrl("jdbc:h2:mem:default");
             dataSource.setUsername("sa");
@@ -61,11 +61,15 @@ public class App {
         }
     }
 
-    private static void someOtherMethod() {
+    private static void someOtherMethod(int level) {
         try {
             TimeUnit.NANOSECONDS.sleep(1);
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
+
+        if (level < 1000) {
+            someOtherMethod(level + 1);
+        }
     }
 }
diff --git a/ui/src/App.css b/ui/src/App.css
index 47910a0..bc993bf 100644
--- a/ui/src/App.css
+++ b/ui/src/App.css
@@ -26,35 +26,15 @@ body {
   left:-20px;
 }
 
-
-
 .tree li input ~ ul{
   display: none;
   height: 0;
 }
-/*
-.tree input  {
-  background: url(toggle-small-expand.png) no-repeat;
-  height: 1em;
-
-
-	content: "\00a0\00a0\00a0"; 
-	overflow: hidden;
-	width: 16px;
-	height: 16px;
-}
-
-.tree input:checked{
-  background: url(toggle-small.png) no-repeat;
-}*/
 
 .tree li input:checked ~ ul{
   display: inline;
 }
-  
-/* .tree li input:checked  { display: block; margin: 0 0 0.125em;  2px} */
-/* .tree li input:checked  li:last-child { margin: 0 0 0.063em; 1px } */
-    
+
 .tree ul {margin-left:1em} /* (indentation/2) */
 
 .tree li:before {
diff --git a/ui/src/Tree.js b/ui/src/Tree.js
index b3dd3d5..c15cfa6 100644
--- a/ui/src/Tree.js
+++ b/ui/src/Tree.js
@@ -24,10 +24,9 @@ class Tree extends Component {
         return (<ul className="tree">
             {children.map(
                 r =>
-                    <li key={r.report.name}><input type="checkbox" className="tree"></input>
-                        {Math.floor(r.report.average / 1000) / 1000} ms &nbsp;
-                        - {r.report.invocations} inv. &nbsp;
-                        {r.report.name}
+                    <li key={r.name}><input type="checkbox" className="tree"/>
+                        {Math.floor(r.invocation.duration / 1000) / 1000} ms &nbsp;
+                        {r.name}
                         {this.renderChildren(r.children)}
                     </li>
             )}