diff --git a/bindings/java/src/org/hyperic/sigar/SigarProxyCache.java b/bindings/java/src/org/hyperic/sigar/SigarProxyCache.java
index fdefa219..9d8fc5fd 100644
--- a/bindings/java/src/org/hyperic/sigar/SigarProxyCache.java
+++ b/bindings/java/src/org/hyperic/sigar/SigarProxyCache.java
@@ -123,7 +123,7 @@ public class SigarProxyCache
      * The java.lang.reflect.InvocationHandler used by the Proxy.
      * This method handles caching of all Sigar type objects.
      */
-    public Object invoke(Object proxy, Method method, Object[] args)
+    public synchronized Object invoke(Object proxy, Method method, Object[] args)
         throws SigarException, SigarNotImplementedException {
 
         SigarCacheObject cacheVal = null;