src/java.xml/share/classes/com/sun/org/apache/xerces/internal/utils/XMLSecurityManager.java

@@ -25,10 +25,12 @@
 
 package com.sun.org.apache.xerces.internal.utils;
 
 import com.sun.org.apache.xerces.internal.impl.Constants;
 import com.sun.org.apache.xerces.internal.util.SecurityManager;
+import java.util.concurrent.CopyOnWriteArrayList;
+import org.xml.sax.SAXException;
 
 /**
  * This class manages standard and implementation-specific limitations.
  *
  */

@@ -494,10 +496,27 @@
             }
         }
 
     }
 
+    // Array list to store printed warnings for each SAX parser used
+    private static final CopyOnWriteArrayList<String> printedWarnings = new CopyOnWriteArrayList<>();
+
+    /**
+     * Prints out warnings if a parser does not support the specified feature/property.
+     *
+     * @param parserClassName the name of the parser class
+     * @param propertyName the property name
+     * @param exception the exception thrown by the parser
+     */
+    public static void printWarning(String parserClassName, String propertyName, SAXException exception) {
+        String key = parserClassName+":"+propertyName;
+        if (printedWarnings.addIfAbsent(key)) {
+            System.err.println( "Warning: "+parserClassName+": "+exception.getMessage());
+        }
+    }
+
     /**
      * Read from system properties, or those in jaxp.properties
      *
      * @param property the type of the property
      * @param sysPropertyName the name of system property