diff --git a/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexInsecureEndpointRule.java b/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexInsecureEndpointRule.java
index ddbffa0c90..8366c40a7a 100644
--- a/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexInsecureEndpointRule.java
+++ b/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexInsecureEndpointRule.java
@@ -29,7 +29,7 @@ public class ApexInsecureEndpointRule extends AbstractApexRule {
     private static final String SET_ENDPOINT = "setEndpoint";
     private static final Pattern PATTERN = Pattern.compile("^http://.+?$", Pattern.CASE_INSENSITIVE);
 
-    private static final Set<String> HTTP_ENDPOINT_STRINGS = new HashSet<>();
+    private final Set<String> httpEndpointStrings = new HashSet<>();
 
     public ApexInsecureEndpointRule() {
         setProperty(CODECLIMATE_CATEGORIES, new String[] { "Security" });
@@ -74,7 +74,7 @@ public class ApexInsecureEndpointRule extends AbstractApexRule {
             if (o instanceof String) {
                 String literal = (String) o;
                 if (PATTERN.matcher(literal).matches()) {
-                    HTTP_ENDPOINT_STRINGS.add(Helper.getFQVariableName(variableNode));
+                    httpEndpointStrings.add(Helper.getFQVariableName(variableNode));
                 }
             }
         }
@@ -114,7 +114,7 @@ public class ApexInsecureEndpointRule extends AbstractApexRule {
 
         ASTVariableExpression variableNode = node.getFirstChildOfType(ASTVariableExpression.class);
         if (variableNode != null) {
-            if (HTTP_ENDPOINT_STRINGS.contains(Helper.getFQVariableName(variableNode))) {
+            if (httpEndpointStrings.contains(Helper.getFQVariableName(variableNode))) {
                 addViolation(data, variableNode);
             }
 
diff --git a/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexXSSFromURLParamRule.java b/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexXSSFromURLParamRule.java
index 3cb2f9557d..c6c80f60da 100644
--- a/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexXSSFromURLParamRule.java
+++ b/pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/rule/security/ApexXSSFromURLParamRule.java
@@ -37,7 +37,7 @@ public class ApexXSSFromURLParamRule extends AbstractApexRule {
     private static final String[] DOUBLE_VALUEOF = new String[] { "Double", "valueOf" };
     private static final String[] STRING_ISEMPTY = new String[] { "String", "isEmpty" };
 
-    private static final Set<String> URL_PARAMETER_STRINGS = new HashSet<>();
+    private final Set<String> urlParameterStrings = new HashSet<>();
 
     public ApexXSSFromURLParamRule() {
         setProperty(CODECLIMATE_CATEGORIES, new String[] { "Security" });
@@ -88,7 +88,7 @@ public class ApexXSSFromURLParamRule extends AbstractApexRule {
         List<ASTVariableExpression> nodes = node.findChildrenOfType(ASTVariableExpression.class);
 
         for (ASTVariableExpression varExpression : nodes) {
-            if (URL_PARAMETER_STRINGS.contains(Helper.getFQVariableName(varExpression))) {
+            if (urlParameterStrings.contains(Helper.getFQVariableName(varExpression))) {
                 addViolation(data, nodes.get(0));
             }
         }
@@ -133,7 +133,7 @@ public class ApexXSSFromURLParamRule extends AbstractApexRule {
                 ASTVariableExpression left = node.getFirstChildOfType(ASTVariableExpression.class);
 
                 if (left != null) {
-                    URL_PARAMETER_STRINGS.add(Helper.getFQVariableName(left));
+                    urlParameterStrings.add(Helper.getFQVariableName(left));
                 }
             }
 
@@ -159,7 +159,7 @@ public class ApexXSSFromURLParamRule extends AbstractApexRule {
                 return;
             }
 
-            if (URL_PARAMETER_STRINGS.contains(Helper.getFQVariableName(variable))) {
+            if (urlParameterStrings.contains(Helper.getFQVariableName(variable))) {
                 if (!isEscapingMethod(methodNode)) {
                     addViolation(data, variable);
                 }
@@ -192,7 +192,7 @@ public class ApexXSSFromURLParamRule extends AbstractApexRule {
             // Look for: foo = bar;
             final ASTVariableExpression right = reverseOrder ? nodes.get(0) : nodes.get(1);
 
-            if (URL_PARAMETER_STRINGS.contains(Helper.getFQVariableName(right))) {
+            if (urlParameterStrings.contains(Helper.getFQVariableName(right))) {
                 addViolation(data, right);
             }
         }
@@ -217,7 +217,7 @@ public class ApexXSSFromURLParamRule extends AbstractApexRule {
         final List<ASTVariableExpression> nodes = node.findChildrenOfType(ASTVariableExpression.class);
         for (ASTVariableExpression n : nodes) {
 
-            if (URL_PARAMETER_STRINGS.contains(Helper.getFQVariableName(n))) {
+            if (urlParameterStrings.contains(Helper.getFQVariableName(n))) {
                 addViolation(data, n);
             }
         }