diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java b/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java
index 5d55493..d061f00 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/JavaMethodBodyGenerator.java
@@ -16,6 +16,7 @@
 import models.algebra.ParameterizedIdentifierIsFutureWork;
 import models.algebra.Symbol;
 import models.algebra.Term;
+import models.algebra.Type;
 import models.algebra.UnificationFailed;
 import models.algebra.ValueUndefined;
 import models.algebra.Variable;
@@ -46,8 +47,80 @@
 		Symbol.Memento sumMem = null;
 		if (sum != null) {
 			sumMem = sum.createMemento();
-			sum.setImplName("stream().mapToInt(x->x).sum");
-			sum.setImplOperatorType(Symbol.Type.METHOD);
+			final int[] count = new int[] {0};
+			sum.setGenerator(new Symbol.IImplGenerator() {
+				@Override
+				public String generate(Type type, String[] children, String[] sideEffects) {
+					String compType = "Integer";
+					if (type != null) {
+						String interfaceType = type.getInterfaceTypeName();
+						if (interfaceType.contains("<")) {
+							compType = interfaceType.substring(interfaceType.indexOf("<") + 1, interfaceType.lastIndexOf(">"));
+						}						
+					}
+					count[0]++;
+					String impl = compType + " " + "temp_sum" + count[0] + " = 0;\n";
+					impl += "for (" + compType + " x: " + children[0] + ") {\n";
+					impl += "\t" + "temp_sum" + count[0] + " += x;\n";
+					impl += "}\n";
+					sideEffects[0] = sideEffects[0] + impl;
+					return "temp_sum" + count[0];
+				}
+			});
+			sum.setImplOperatorType(Symbol.Type.GENERATIVE);
+//			sum.setImplName("stream().mapToInt(x->x).sum");
+//			sum.setImplOperatorType(Symbol.Type.METHOD);
+		}
+		Symbol merge = model.getSymbol("merge");
+		Symbol.Memento mergeMem = null;
+		if (merge != null) {
+			mergeMem = merge.createMemento();
+			merge.setArity(2);
+			final int[] count = new int[] {0};
+			merge.setGenerator(new Symbol.IImplGenerator() {
+				@Override
+				public String generate(Type type, String[] childrenImpl, String[] sideEffects) {
+					String implType = "Arrayist<>";
+					String interfaceType = "List<Integer>";
+					String compType = "Integer";
+					if (type != null) {
+						implType = type.getImplementationTypeName();
+						interfaceType = type.getInterfaceTypeName();
+						if (interfaceType.contains("<")) {
+							compType = interfaceType.substring(interfaceType.indexOf("<") + 1, interfaceType.lastIndexOf(">"));
+						}
+					}
+					String idxGetter = "";
+					if (compType.startsWith("AbstractMap.SimpleEntry")) {
+						idxGetter = ".getKey()";
+					}
+					count[0]++;
+					String impl = "";
+					impl += "" + interfaceType + " temp_l" + count[0] + " = new " + implType + "();\n";
+					impl += "Iterator<" + compType + "> i1 = " + childrenImpl[0] + ".iterator();\n";
+					impl += "Iterator<" + compType + "> i2 = " + childrenImpl[1] + ".iterator();\n";
+					impl += compType + " t1 = null;\n";
+					impl += compType + " t2 = null;\n";
+					impl += "while (i1.hasNext() || i2.hasNext()) {\n";
+					impl += "\tif (t1 == null && i1.hasNext()) {\n";
+					impl += "\t\tt1 = i1.next();\n";
+					impl += "\t}\n";
+					impl += "\tif (t2 == null && i2.hasNext()) {\n";
+					impl += "\t\tt2 = i2.next();\n";
+					impl += "\t}\n";
+					impl += "\tif (t1 == null || (t2 != null && t1" + idxGetter + " > t2" + idxGetter + ")) {\n";
+					impl += "\t\ttemp_l"  + count[0] +".add(t2);\n";
+					impl += "\t\tt2 = null;\n";
+					impl += "\t} else {\n";
+					impl += "\t\ttemp_l" + count[0] + ".add(t1);\n";
+					impl += "\t\tt1 = null;\n";
+					impl += "\t}\n";
+					impl += "}\n";
+					sideEffects[0] = sideEffects[0] + impl;
+					return "temp_l" + count[0];
+				}
+			});
+			merge.setImplOperatorType(Symbol.Type.GENERATIVE);
 		}
 
 		// Create a map from type names (lower case) to their types.
@@ -77,12 +150,13 @@
 							if (((StoreAttribute) dst.getAttribute()).isStored()) {
 								// update stored state of dst resource (when every incoming edge is in push style)
 								Expression updateExp = d.getChannelGenerator().deriveUpdateExpressionOf(out, JavaCodeGenerator.pushAccessor);
-								String curState = updateExp.toImplementation();
+								String[] sideEffects = new String[] {""};
+								String curState = updateExp.toImplementation(sideEffects);
 								String updateStatement;
 								if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
-									updateStatement = curState + ";";								
+									updateStatement = sideEffects[0];
 								} else {
-									updateStatement = dstResourceName + " = " + curState + ";";
+									updateStatement = sideEffects[0] + dstResourceName + " = " + curState + ";";
 								}
 								if (update.getBody() == null || !update.getBody().getStatements().contains(updateStatement)) {
 									update.addFirstStatement(updateStatement);
@@ -123,14 +197,15 @@
 										inputIdentifierToStateAccessor.put(((ResourceNode) dIn.getSource()).getIdentifierTemplate(), JavaCodeGenerator.pullAccessor);
 									}
 								}
+								String[] sideEffects = new String[] {""};
 								if (!isContainedPush) {
 									// All incoming edges are in PULL style.
-									String curState = d.getChannelGenerator().deriveUpdateExpressionOf(out, JavaCodeGenerator.pullAccessor).toImplementation();
-									getter.addStatement("return " + curState + ";");
+									String curState = d.getChannelGenerator().deriveUpdateExpressionOf(out, JavaCodeGenerator.pullAccessor).toImplementation(sideEffects);
+									getter.addStatement(sideEffects[0] + "return " + curState + ";");
 								} else {
 									// At least one incoming edge is in PUSH style.
-									String curState = d.getChannelGenerator().deriveUpdateExpressionOf(out, JavaCodeGenerator.pullAccessor, inputIdentifierToStateAccessor).toImplementation();
-									getter.addStatement("return " + curState + ";");
+									String curState = d.getChannelGenerator().deriveUpdateExpressionOf(out, JavaCodeGenerator.pullAccessor, inputIdentifierToStateAccessor).toImplementation(sideEffects);
+									getter.addStatement(sideEffects[0] + "return " + curState + ";");
 								}
 							}
 						} 
@@ -157,13 +232,14 @@
 						Term message = (Term) out.getStateTransition().getMessageExpression();
 						MethodDeclaration input = getMethod(type, message.getSymbol().getName());
 						if (input != null) {
+							String[] sideEffects = new String[] {""};
 							Expression updateExp = ioChannelAndMember.getKey().deriveUpdateExpressionOf(out, JavaCodeGenerator.pushAccessor);
-							String newState = updateExp.toImplementation();
+							String newState = updateExp.toImplementation(sideEffects);
 							String updateStatement;
 							if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
-								updateStatement = newState + ";";								
+								updateStatement = sideEffects[0];	
 							} else {
-								updateStatement = "this." + resourceName + " = " + newState + ";";
+								updateStatement = sideEffects[0] + "this." + resourceName + " = " + newState + ";";
 							}
 							if (input.getBody() == null || !input.getBody().getStatements().contains(updateStatement)) {
 								input.addFirstStatement(updateStatement);
@@ -191,6 +267,7 @@
 		
 		if (floor != null) floor.setMemento(floorMem);
 		if (sum != null) sum.setMemento(sumMem);
+		if (merge != null) merge.setMemento(mergeMem);
 		return codes;
 	}