Refactor creation of ExpressionFactory

ELUtil doesn't require a factory for all operations whereas the
ELManager does. Moving construction of the factory to the ELManager
allows some limited unit testing of ELUtil without placing additional
limits on how ELManager can be used.

api/src/main/java/jakarta/el/ELContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021 Oracle and/or its affiliates and others.
+ * Copyright (c) 1997, 2022 Oracle and/or its affiliates and others.
  * All rights reserved.
  * Copyright 2004 The Apache Software Foundation
  *
@@ -439,7 +439,7 @@ public <T> T convertToType(Object obj, Class<T> targetType) {
 
         ExpressionFactory exprFactory = (ExpressionFactory) getContext(ExpressionFactory.class);
         if (exprFactory == null) {
-            exprFactory = ELUtil.getExpressionFactory();
+            exprFactory = ELManager.getExpressionFactory();
         }
 
         return exprFactory.coerceToType(obj, targetType);

api/src/main/java/jakarta/el/ELManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2019 Oracle and/or its affiliates and others.
+ * Copyright (c) 2013, 2022 Oracle and/or its affiliates and others.
  * All rights reserved.
  *
  * This program and the accompanying materials are made available under the
@@ -27,6 +27,8 @@
  */
 public class ELManager {
 
+    private static ExpressionFactory exprFactory = ExpressionFactory.newInstance();
+
     private StandardELContext elContext;
 
     /**
@@ -35,7 +37,7 @@ public class ELManager {
      * @return The ExpressionFactory
      */
     public static ExpressionFactory getExpressionFactory() {
-        return ELUtil.getExpressionFactory();
+        return exprFactory;
     }
 
     /**

api/src/main/java/jakarta/el/ELUtil.java

@@ -53,8 +53,6 @@ class ELUtil {
     private ELUtil() {
     }
 
-    public static ExpressionFactory exprFactory = ExpressionFactory.newInstance();
-
     /**
      * <p>
      * The <code>ThreadLocal</code> variable used to record the <code>jakarta.faces.context.FacesContext</code> instance for
@@ -161,10 +159,6 @@ public static String getExceptionMessageString(ELContext context, String message
         return result;
     }
 
-    static ExpressionFactory getExpressionFactory() {
-        return exprFactory;
-    }
-
     static Constructor<?> findConstructor(Class<?> klass, Class<?>[] paramTypes, Object[] params) {
         String methodName = "<init>";
 
@@ -533,7 +527,7 @@ private static boolean isCoercibleFrom(Object src, Class<?> target) {
         // TODO: This isn't pretty but it works. Significant refactoring would
         // be required to avoid the exception.
         try {
-            getExpressionFactory().coerceToType(src, target);
+            ELManager.getExpressionFactory().coerceToType(src, target);
         } catch (Exception e) {
             return false;
         }