diff --git a/ws2012/P2P/uebungen/4/.classpath b/ws2012/P2P/uebungen/4/.classpath
new file mode 100644
index 00000000..fb501163
--- /dev/null
+++ b/ws2012/P2P/uebungen/4/.classpath
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>
diff --git a/ws2012/P2P/uebungen/4/.project b/ws2012/P2P/uebungen/4/.project
new file mode 100644
index 00000000..fd9846f2
--- /dev/null
+++ b/ws2012/P2P/uebungen/4/.project
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>4</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>
diff --git a/ws2012/P2P/uebungen/4/src/common/MessageType.java b/ws2012/P2P/uebungen/4/src/common/MessageType.java
new file mode 100644
index 00000000..01f7ceeb
--- /dev/null
+++ b/ws2012/P2P/uebungen/4/src/common/MessageType.java
@@ -0,0 +1,7 @@
+package common;
+
+public class MessageType {
+	public final static byte BOOTSTRAP = 0;
+	public final static byte LEAVE = 1;
+	public final static byte NEW_NEIGHBOUR = 1;
+}
diff --git a/ws2012/P2P/uebungen/4/src/peer/Node.java b/ws2012/P2P/uebungen/4/src/peer/Node.java
index dfe72755..da7c4885 100644
--- a/ws2012/P2P/uebungen/4/src/peer/Node.java
+++ b/ws2012/P2P/uebungen/4/src/peer/Node.java
@@ -5,9 +5,10 @@ import java.util.List;
 
 public class Node {
 	
-	private int id; // node id must be unique! id = IP of peer ?!?
-					//-> Should be unique if we don't consider peers behind a NAT.
-	
+	// node id must be unique! id = IP of peer ?!?
+	// -> Should be unique if we don't consider peers behind a NAT.
+	private int id;
+
 	private List<Node> neighbours;
 	
 	public Node(int id, List<Node> neighbours){
@@ -16,12 +17,20 @@ public class Node {
 	}
 	
 	
-	//add one single neighbour
+	/**
+	 * Add one single neighbour
+	 * 
+	 * @param neighbour
+	 */
 	public void addSingleNeighbour(Node neighbour){
 		this.neighbours.add(neighbour);
 	}
 	
-	//add a list of new neighbours
+	/**
+	 * Add a list of new neighbours
+	 * 
+	 * @param neighbours
+	 */
 	public void addMultiNeighbours(List<Node> neighbours){
 		Iterator<Node> it = neighbours.iterator();
 		while(it.hasNext()){
@@ -33,7 +42,12 @@ public class Node {
 		return (this.neighbours.size() > 0);
 	}
 	
-	//checks if actual node has neighbour with given id
+	/**
+	 * checks if actual node has neighbour with given id
+	 * 
+	 * @param id
+	 * @return
+	 */
 	public boolean hasNeighbour(int id){
 		for(int i = 0; i < neighbours.size(); i++){
 			Node tmp = neighbours.get(i);
@@ -43,8 +57,4 @@ public class Node {
 		}
 		return false;
 	}
-	
-	
-	
-
-}
+}
\ No newline at end of file
diff --git a/ws2012/P2P/uebungen/4/src/peer/Peer.java b/ws2012/P2P/uebungen/4/src/peer/Peer.java
index c0f14dc6..69fca905 100644
--- a/ws2012/P2P/uebungen/4/src/peer/Peer.java
+++ b/ws2012/P2P/uebungen/4/src/peer/Peer.java
@@ -2,30 +2,23 @@ package peer;
 
 
 public class Peer {
-	
+
 	private Node node;
-	
-	
-	//create another peer, mutually link creator and spawn
-	public void spawn(){
-		
+
+	/**
+	 * Create another peer, mutually link creator and spawn.
+	 */
+	public void spawn() {
+
 	}
-	
-	
-	
-	//circularly link all neighbours, remove itself form all neighbours and exit
-	public void leave(){
-		
+
+	/**
+	 * Circularly link all neighbours, remove itself form all neighbours and
+	 * exit.
+	 */
+	public void leave() {
+
 	}
-	
-	
-	
-	
-	
-	
-	
-	
-	
-	
+
 
 }