diff --git a/makefile b/makefile
index cc59d0d..ec0993a 100644
--- a/makefile
+++ b/makefile
@@ -29,6 +29,9 @@ test-jar: jar
 # 	$(JR) -cp "$(OUT_DIR)/:$(LIB_DIR)/*" $(MAIN_CLASS)
 	$(JR) -jar $(OUT_DIR)/$(JAR_NAME)
 
+docs:
+	javadoc -cp "$(LIB_DIR)/*" -d "docs" $(SRC_DIR)/*.java
+
 test: classfiles
 	$(JR) -cp "$(OUT_DIR)$(SEPERATOR)$(LIB_DIR)/*" $(MAIN_CLASS)
 
diff --git a/src/AiPlayer.java b/src/AiPlayer.java
index 071f896..a1c9690 100644
--- a/src/AiPlayer.java
+++ b/src/AiPlayer.java
@@ -155,6 +155,7 @@ public abstract class AiPlayer extends LocalPlayer implements Runnable {
         while(i.hasNext()) {
             Thread thread = i.next();
             try {
+                thread.interrupt();
                 thread.join();
                 i.remove();
             } catch (InterruptedException e) {
diff --git a/src/BoardDisplay.java b/src/BoardDisplay.java
index 5295ad7..d0eeedd 100644
--- a/src/BoardDisplay.java
+++ b/src/BoardDisplay.java
@@ -174,6 +174,7 @@ public class BoardDisplay extends JPanel {
         if(currentShip != null) {
             test = currentShip.getVirtualOccupiedPoints(mousePosition, horizontal);
         }
+        if (player == null || player.getBoard() == null) return;
         for(int i = 0; i < gridSize; i++) {
             for(int j = 0; j < gridSize; j++) {
                 if(fields[i][j] == null) {
diff --git a/src/MainFrame.java b/src/MainFrame.java
index 004c068..f327e0b 100644
--- a/src/MainFrame.java
+++ b/src/MainFrame.java
@@ -129,7 +129,7 @@ public class MainFrame extends JFrame {
      * @author Lucas Bronson, Peer Ole Wachtel, Luca Conte
      */
     public void showPanelWin(String panelName, Player player){
-        if(player != gameBoard.getP1()){
+        if(gameBoard == null || player != gameBoard.getP1()){
             return;
         }
 
@@ -152,7 +152,7 @@ public class MainFrame extends JFrame {
      * @author Lucas Bronson, Peer Ole Wachtel, Luca Conte
      */
     public void showPanelLose(String panelName, Player player){
-        if(player != gameBoard.getP1()){
+        if(gameBoard == null || player != gameBoard.getP1()){
             return;
         }