diff --git a/java.editor/src/org/netbeans/modules/editor/java/Utilities.java b/java.editor/src/org/netbeans/modules/editor/java/Utilities.java
--- a/java.editor/src/org/netbeans/modules/editor/java/Utilities.java
+++ b/java.editor/src/org/netbeans/modules/editor/java/Utilities.java
@@ -166,6 +166,43 @@
             return false;
         if (prefix == null || prefix.length() == 0)
             return true;
+        
+        // sub word completion
+        {
+            // example:
+            // 'out' produces '.*?[o|O].*?[u|U].*?[t|T].*?'
+            // org.openide.util.Utilities.acoh -> actionsForPath
+            // java.lang.System.out -> setOut
+            // argex -> IllegalArgumentException
+            // java.util.Collections.que -> asLifoQueue
+            // java.lang.System.sin -> setIn, getSecurityManager, setSecurityManager
+            
+            // check whether user input matches the regex
+            StringBuilder sb = new StringBuilder(3+8*prefix.length());
+            sb.append(".*?");
+            for (int i = 0; i < prefix.length(); i++) {
+                char charAt = prefix.charAt(i);
+                if (Character.isLowerCase(charAt)) {
+                    sb.append("[");
+                    sb.append(charAt);
+                    sb.append("|");
+                    sb.append(Character.toUpperCase(charAt));
+                    sb.append("]");
+                } else {
+                    //keep uppercase characters as beacons
+                    // for example: java.lang.System.sIn -> setIn
+                    sb.append(charAt);
+                }
+                sb.append(".*?");
+            }
+            
+             System.out.println(sb);
+            // FIXME regex matches are expensive
+            if (Pattern.compile(sb.toString()).matcher(theString).matches()) {
+                return true;
+            };
+        }
+        
         return isCaseSensitive() ? theString.startsWith(prefix) :
             theString.toLowerCase(Locale.ENGLISH).startsWith(prefix.toLowerCase(Locale.ENGLISH));
     }