diff --git a/core/src/main/java/com/opensymphony/xwork2/security/DefaultAcceptedPatternsChecker.java b/core/src/main/java/com/opensymphony/xwork2/security/DefaultAcceptedPatternsChecker.java
index 4d2caa594..be803b7e8 100644
--- a/core/src/main/java/com/opensymphony/xwork2/security/DefaultAcceptedPatternsChecker.java
+++ b/core/src/main/java/com/opensymphony/xwork2/security/DefaultAcceptedPatternsChecker.java
@@ -31,6 +31,7 @@ import java.util.regex.Pattern;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.unmodifiableSet;
+import static java.util.stream.Collectors.joining;
 
 public class DefaultAcceptedPatternsChecker implements AcceptedPatternsChecker {
 
@@ -44,6 +45,7 @@ public class DefaultAcceptedPatternsChecker implements AcceptedPatternsChecker {
      * Must match {@link #ACCEPTED_PATTERNS} RegEx. Signifies characters which result in a nested lookup via OGNL.
      */
     public static final Set<Character> NESTING_CHARS = unmodifiableSet(new HashSet<>(asList('.', '[', '(')));
+    public static final String NESTING_CHARS_STR = NESTING_CHARS.stream().map(String::valueOf).collect(joining());
 
     public static final String[] DMI_AWARE_ACCEPTED_PATTERNS = {
             "\\w+([:]?\\w+)?((\\.\\w+)|(\\[\\d+])|(\\(\\d+\\))|(\\['(\\w-?|[\\u4e00-\\u9fa5]-?)+'])|(\\('(\\w-?|[\\u4e00-\\u9fa5]-?)+'\\)))*([!]?\\w+)?"
diff --git a/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java b/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java
index 1443fddeb..71c84d195 100644
--- a/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java
+++ b/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java
@@ -63,6 +63,7 @@ import java.util.TreeMap;
 import java.util.regex.Pattern;
 
 import static com.opensymphony.xwork2.security.DefaultAcceptedPatternsChecker.NESTING_CHARS;
+import static com.opensymphony.xwork2.security.DefaultAcceptedPatternsChecker.NESTING_CHARS_STR;
 import static java.util.Collections.unmodifiableSet;
 import static java.util.stream.Collectors.joining;
 import static org.apache.commons.lang3.StringUtils.indexOfAny;
@@ -340,7 +341,7 @@ public class ParametersInterceptor extends MethodFilterInterceptor {
             return true;
         }
 
-        int nestingIndex = indexOfAny(name, NESTING_CHARS.stream().map(String::valueOf).collect(joining()));
+        int nestingIndex = indexOfAny(name, NESTING_CHARS_STR);
         String rootProperty = nestingIndex == -1 ? name : name.substring(0, nestingIndex);
         long paramDepth = name.codePoints().mapToObj(c -> (char) c).filter(NESTING_CHARS::contains).count();