diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassSpecialization.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassSpecialization.java
index f8448c63acc..0e7fb8901b1 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassSpecialization.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassSpecialization.java
@@ -64,14 +64,22 @@ public class CPPClassSpecialization extends CPPSpecialization
 	}
 	
 	public IBinding specializeMember(IBinding original) {		
-		IBinding result= (IBinding) specializationMap.get(original);
-		if (result == null) {
-			result= CPPTemplates.createSpecialization(this, original, argumentMap);
+		synchronized(this) {
+			IBinding result= (IBinding) specializationMap.get(original);
+			if (result != null) 
+				return result;
+		}
+		
+		IBinding result= CPPTemplates.createSpecialization(this, original, argumentMap);
+		synchronized(this) {
+			IBinding concurrent= (IBinding) specializationMap.get(original);
+			if (concurrent != null) 
+				return concurrent;
 			if (specializationMap == ObjectMap.EMPTY_MAP)
 				specializationMap = new ObjectMap(2);
 			specializationMap.put(original, result);
+			return result;
 		}
-		return result;
 	}
 	
 	private class FindDefinitionAction extends CPPASTVisitor {
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassTemplateSpecialization.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassTemplateSpecialization.java
index 576c2f19034..3e4ab6761be 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassTemplateSpecialization.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPClassTemplateSpecialization.java
@@ -49,13 +49,13 @@ public class CPPClassTemplateSpecialization extends CPPClassSpecialization
 		return template.getTemplateParameters();
 	}
 
-	public void addInstance(IType[] arguments, ICPPTemplateInstance instance) {
+	public synchronized void addInstance(IType[] arguments, ICPPTemplateInstance instance) {
 		if (instances == null)
 			instances = new ObjectMap(2);
 		instances.put(arguments, instance);
 	}
 
-	public ICPPTemplateInstance getInstance(IType[] arguments) {
+	public synchronized ICPPTemplateInstance getInstance(IType[] arguments) {
 		if (instances != null) {
 			loop: for (int i=0; i < instances.size(); i++) {
 				IType[] args = (IType[]) instances.keyAt(i);
@@ -72,7 +72,7 @@ public class CPPClassTemplateSpecialization extends CPPClassSpecialization
 		return null;
 	}
 
-	public ICPPTemplateInstance[] getAllInstances() {
+	public synchronized ICPPTemplateInstance[] getAllInstances() {
 		if (instances != null) {
 			ICPPTemplateInstance[] result= new ICPPTemplateInstance[instances.size()];
 			for (int i=0; i < instances.size(); i++) {
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPFunctionTemplateSpecialization.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPFunctionTemplateSpecialization.java
index 81fbe76fe65..c9ae10589e4 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPFunctionTemplateSpecialization.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPFunctionTemplateSpecialization.java
@@ -39,13 +39,13 @@ public class CPPFunctionTemplateSpecialization extends CPPFunctionSpecialization
 		return template.getTemplateParameters();
 	}
 
-	public final void addInstance(IType[] arguments, ICPPTemplateInstance instance) {
+	public synchronized final void addInstance(IType[] arguments, ICPPTemplateInstance instance) {
 		if (instances == null)
 			instances = new ObjectMap(2);
 		instances.put(arguments, instance);
 	}
 
-	public final ICPPTemplateInstance getInstance(IType[] arguments) {
+	public synchronized final ICPPTemplateInstance getInstance(IType[] arguments) {
 		if (instances != null) {
 			loop: for (int i=0; i < instances.size(); i++) {
 				IType[] args = (IType[]) instances.keyAt(i);
@@ -62,7 +62,7 @@ public class CPPFunctionTemplateSpecialization extends CPPFunctionSpecialization
 		return null;
 	}
 	
-	public ICPPTemplateInstance[] getAllInstances() {
+	public synchronized ICPPTemplateInstance[] getAllInstances() {
 		if (instances != null) {
 			ICPPTemplateInstance[] result= new ICPPTemplateInstance[instances.size()];
 			for (int i=0; i < instances.size(); i++) {