diff --git a/core/src/main/java/hudson/maven/ProcessCache.java b/core/src/main/java/hudson/maven/ProcessCache.java
index 3f65b87b3fa61e65f7dc51b8c9cac90a7f0579ed..af24d9279fd183eb1d5df5e23d4a0aa023ba97d6 100644
--- a/core/src/main/java/hudson/maven/ProcessCache.java
+++ b/core/src/main/java/hudson/maven/ProcessCache.java
@@ -108,7 +108,7 @@ public final class ProcessCache {
         }
     }
 
-    class PerChannel {
+    static class PerChannel {
         /**
          * Cached processes.
          */