Fix for not being able to unlock multithreading

src/main/java/de/hhu/ba/yoshikoWrapper/core/AlgorithmTask.java

@@ -84,10 +84,11 @@ public class AlgorithmTask extends AbstractTask {
 
 		taskMonitor.setTitle(LocalizationManager.get("yoshTask"));
 		taskMonitor.setProgress(0.0);
+		
 		//Get current network
 		if (net == null) {
 			logger.warn("CoreAlgorithm called on a net that is NULL!");
-			return;
+			throw new Exception("CoreAlgorithm called on a net that is NULL!");
 		}
 		
 		//Set time limit
@@ -95,6 +96,9 @@ public class AlgorithmTask extends AbstractTask {
 		if (parameterSet.disableMultiThreading) {
 			LibraryInterface.setThreadLimit(1);
 		}
+		else {
+			LibraryInterface.setThreadLimit(0);
+		}
 
 		//Create a node map to identify nodes and eges in the solution
 		NodeMap nodeMap  = new NodeMap(net);