Improve XML parser issue reporting

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@272535 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/Main.java

@@ -565,21 +565,7 @@ public class Main {
                 project.setUserProperty("ant.file",
                     buildFile.getAbsolutePath());
 
-                // first use the ProjectHelper to create the project object
-                // from the given build file.
-                String noParserMessage = "No JAXP compliant XML parser found. "
-                    + "Please visit http://xml.apache.org "
-                    + "for a suitable parser";
-                try {
-                    Class.forName("javax.xml.parsers.SAXParserFactory");
-                    ProjectHelper.configureProject(project, buildFile);
-                } catch (NoClassDefFoundError ncdfe) {
-                    throw new BuildException(noParserMessage, ncdfe);
-                } catch (ClassNotFoundException cnfe) {
-                    throw new BuildException(noParserMessage, cnfe);
-                } catch (NullPointerException npe) {
-                    throw new BuildException(noParserMessage, npe);
-                }
+                ProjectHelper.configureProject(project, buildFile);
 
                 if (projectHelp) {
                     printDescription(project);

src/main/org/apache/tools/ant/ProjectHelper.java

@@ -139,7 +139,7 @@ public class ProjectHelper {
             + "in a helper plugin " + this.getClass().getName());
     }
 
-    
+
     /** 
      * Discovers a project helper instance. Uses the same patterns
      * as JAXP, commons-logging, etc: a system property, a JDK1.3
@@ -159,14 +159,15 @@ public class ProjectHelper {
         ProjectHelper helper = null;
         
         // First, try the system property
+        String helperClass = System.getProperty(HELPER_PROPERTY);
         try {
-            String helperClass = System.getProperty(HELPER_PROPERTY);
             if (helperClass != null) {
                 helper = newHelper(helperClass);
             }
         } catch (SecurityException e) {
-            // It's ok, we'll try next option
-            ;
+            System.out.println("Unable to load ProjectHelper class \"" 
+                + helperClass + " specified in system property " 
+                + HELPER_PROPERTY);
         }
 
         // A JDK1.3 'service' ( like in JAXP ). That will plug a helper
@@ -203,15 +204,22 @@ public class ProjectHelper {
                     }
                 }
             } catch (Exception ex) {
-                ;
+                System.out.println("Unable to load ProjectHelper " 
+                    + "from service \"" + SERVICE_ID); 
             }
         }
 
         if (helper != null) {
             return helper;
         } else {
-            // Default
-            return new ProjectHelperImpl();
+            try {
+                // Default
+                return new ProjectHelperImpl();
+            } catch (Throwable e) {
+                String message = "Unable to load default ProjectHelper due to "
+                    + e.getClass().getName() + ": " + e.getMessage();
+                throw new BuildException(message, e);
+            }
         }
     }
 

src/main/org/apache/tools/ant/helper/ProjectHelperImpl.java

@@ -71,7 +71,7 @@ import org.xml.sax.helpers.XMLReaderAdapter;
 import javax.xml.parsers.SAXParserFactory;
 import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.ParserConfigurationException;
-
+import javax.xml.parsers.FactoryConfigurationError;
 import org.apache.tools.ant.ProjectHelper;
 import org.apache.tools.ant.UnknownElement;
 import org.apache.tools.ant.Project;
@@ -165,6 +165,9 @@ public class ProjectHelperImpl extends ProjectHelper {
             parser.parse(inputSource);
         } catch (ParserConfigurationException exc) {
             throw new BuildException("Parser has not been configured correctly", exc);
+        } catch (FactoryConfigurationError e) {
+            throw new BuildException("XML parser has not been configured " 
+                + "correctly: " + e.getMessage(), e);
         } catch (SAXParseException exc) {
             Location location =
                 new Location(buildFile.toString(), exc.getLineNumber(),