Avoid duplicate processing with selective locking, improving performance.
diff --git a/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/TypeDescriptor.java b/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/TypeDescriptor.java
index ed66893..aea1298 100755
--- a/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/TypeDescriptor.java
+++ b/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/TypeDescriptor.java
@@ -208,14 +208,17 @@
 
     @Override
     protected void init() {
-        typeCode = genTypeCode();
+        getTypeCode();
     }
 
     private volatile TypeCode typeCode = null;
     protected abstract TypeCode genTypeCode();
     final TypeCode getTypeCode() {
-        // typeCode should have already been set from within init(), so this is just defensive
-        if (null == typeCode) typeCode = genTypeCode();
+        if (null == typeCode) {
+            synchronized (repo) {
+                if (null == typeCode) typeCode = genTypeCode();
+            }
+        }
         return typeCode;
     }
     protected final void setTypeCode(TypeCode tc) {
diff --git a/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/ValueDescriptor.java b/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/ValueDescriptor.java
index eb91e9f..6e66d1c 100755
--- a/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/ValueDescriptor.java
+++ b/yoko-rmi-impl/src/main/java/org/apache/yoko/rmi/impl/ValueDescriptor.java
@@ -831,9 +831,12 @@
         return members;
     }
     final ValueMember[] getValueMembers() {
-        getTypeCode(); // ensure recursion through typecode for non-array types
-
-        if (null == valueMembers) valueMembers = genValueMembers();
+        getTypeCode(); // ensure recursion through typecode
+        if (null == valueMembers) {
+            synchronized (repo) {
+                if (null == valueMembers) valueMembers = genValueMembers();
+            }
+        }
         return valueMembers;
     }