diff --git a/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java b/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java
index 17edb0c..cf3f036 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java
@@ -4,6 +4,7 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -198,8 +199,19 @@
 			}
 			if (constructor != null) {
 				for (VariableDeclaration param: params) {
-					constructor.addParameter(param);
-					constructor.getBody().addStatement(langSpec.getFieldAccessor(langSpec.toVariableName(param.getName())) + langSpec.getAssignment() + langSpec.toVariableName(param.getName()) + langSpec.getStatementDelimiter());
+					boolean existsParam = false;
+					if (constructor.getParameters() != null) {
+						for (VariableDeclaration constParam: constructor.getParameters()) {
+							if (constParam.getName().equals(param.getName())) {
+								existsParam = true;
+								break;
+							}
+						}
+					}
+					if (!existsParam) {
+						constructor.addParameter(param);
+						constructor.getBody().addStatement(langSpec.getFieldAccessor(langSpec.toVariableName(param.getName())) + langSpec.getAssignment() + langSpec.toVariableName(param.getName()) + langSpec.getStatementDelimiter());
+					}
 				}
 			}
 		}
@@ -211,7 +223,9 @@
 		Type replacedJsonType = childRes.getResourceStateType();
 		String replacingClassName = getComponentName(childRes, langSpec);
 		Map<Position, Term> subTerms = ((Term) exp).getSubTerms(Term.class);
-		for (Entry<Position, Term> termEnt: subTerms.entrySet()) {
+		Iterator<Entry<Position, Term>> termEntItr = subTerms.entrySet().iterator();
+		while (termEntItr.hasNext()) {
+			Entry<Position, Term> termEnt = termEntItr.next();
 			Term jsonTerm = termEnt.getValue();
 			if (jsonTerm.getType().equals(replacedJsonType)) {
 				MethodDeclaration childConstructor = getConstructor(childComponent);
@@ -228,6 +242,8 @@
 					}
 				}
 				((Term) exp).replaceSubTerm(termEnt.getKey(), new Constant(langSpec.getConstructorInvocation(replacingClassName, params)));
+				subTerms = ((Term) exp).getSubTerms(Term.class);
+				termEntItr = subTerms.entrySet().iterator();
 			}
 		}
 		String[] sideEffects = new String[] {""};
@@ -392,7 +408,16 @@
 						Type dstRootResType = new Type(dstRootResName, dstRootResName);
 						dstRootResName = langSpec.toVariableName(dstRootResName);
 						FieldDeclaration refRootFieldForPush = langSpec.newFieldDeclaration(dstRootResType, dstRootResName);
-						parentComponent.addField(refRootFieldForPush);
+						boolean existsField = false;
+						for (FieldDeclaration field: parentComponent.getFields()) {
+							if (dstRootResName.equals(field.getName())) {
+								existsField = true;
+								break;
+							}
+						}
+						if (!existsField) {
+							parentComponent.addField(refRootFieldForPush);
+						}
 						constructorParams.add(new AbstractMap.SimpleEntry<>(resourceNode.getParent().getResourceHierarchy(), langSpec.newVariableDeclaration(dstRootResType, dstRootResName)));
 					}
 				}
@@ -426,7 +451,16 @@
 						Type srcRootResType = new Type(srcRootResName, srcRootResName);
 						srcRootResName = langSpec.toVariableName(srcRootResName);
 						FieldDeclaration refRootFieldForPull = langSpec.newFieldDeclaration(srcRootResType, srcRootResName);
-						parentComponent.addField(refRootFieldForPull);
+						boolean existsField = false;
+						for (FieldDeclaration field: parentComponent.getFields()) {
+							if (srcRootResName.equals(field.getName())) {
+								existsField = true;
+								break;
+							}
+						}
+						if (!existsField) {
+							parentComponent.addField(refRootFieldForPull);
+						}
 						constructorParams.add(new AbstractMap.SimpleEntry<>(resourceNode.getParent().getResourceHierarchy(), langSpec.newVariableDeclaration(srcRootResType, srcRootResName)));
 					}
 					noPullTransfer = false;
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java b/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java
index 93e3e7b..b383fb1 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java
@@ -718,7 +718,16 @@
 		
 		// Add leaf reference fields to the parent components.
 		for (Map.Entry<ResourceHierarchy, FieldDeclaration> entry: fields) {
-			resourceComponents.get(entry.getKey()).addField(entry.getValue());
+			boolean existsField = false;
+			for (FieldDeclaration field: resourceComponents.get(entry.getKey()).getFields()) {
+				if (field.getName().equals(entry.getValue().getName())) {
+					existsField = true;
+					break;
+				}
+			}
+			if (!existsField) {
+				resourceComponents.get(entry.getKey()).addField(entry.getValue());
+			}
 		}
 		
 		// Add constructor parameters to the ancestor components.
@@ -890,8 +899,19 @@
 			}
 			if (constructor != null) {
 				for (VariableDeclaration param: params) {
-					constructor.addParameter(param);
-					constructor.getBody().addStatement("this." + toVariableName(param.getName()) + " = " + toVariableName(param.getName()) + ";");
+					boolean existsParam = false;
+					if (constructor.getParameters() != null) {
+						for (VariableDeclaration constParam: constructor.getParameters()) {
+							if (constParam.getName().equals(param.getName())) {
+								existsParam = true;
+								break;
+							}
+						}
+					}
+					if (!existsParam) {
+						constructor.addParameter(param);
+						constructor.getBody().addStatement("this." + toVariableName(param.getName()) + " = " + toVariableName(param.getName()) + ";");
+					}
 				}
 			}
 		}
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/JavaMethodBodyGenerator.java b/AlgebraicDataflowArchitectureModel/src/generators/JavaMethodBodyGenerator.java
index f4df963..b4fde5e 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/JavaMethodBodyGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/JavaMethodBodyGenerator.java
@@ -3,6 +3,7 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -589,7 +590,9 @@
 
 	private static void replaceJsonTermWithConstructorInvocation(Expression exp, Type replacedJsonType, String replacingClassName, TypeDeclaration childComponent) {
 		Map<Position, Term> subTerms = ((Term) exp).getSubTerms(Term.class);
-		for (Entry<Position, Term> termEnt: subTerms.entrySet()) {
+		Iterator<Entry<Position, Term>> termEntItr = subTerms.entrySet().iterator();
+		while (termEntItr.hasNext()) {
+			Entry<Position, Term> termEnt = termEntItr.next();
 			Term jsonTerm = termEnt.getValue();
 			if (jsonTerm.getType().equals(replacedJsonType)) {
 				String constructorInvocation = "new " + replacingClassName + "(";
@@ -609,6 +612,8 @@
 				}
 				constructorInvocation += ")";
 				((Term) exp).replaceSubTerm(termEnt.getKey(), new Constant(constructorInvocation));
+				subTerms = ((Term) exp).getSubTerms(Term.class);
+				termEntItr = subTerms.entrySet().iterator();
 			}
 		}
 	}