Better reporting of errors when JAXP not present.

Catch NoClassDefFoundError as well as NullPointerException and
emit a more meaningful error message.

Change BuildException to accept Errors as well as Exceptions
as cause.

Submitted by:	Stefan Bodewig <bodewig@bost.de>


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@267682 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -63,7 +63,7 @@ package org.apache.tools.ant;
 public class BuildException extends RuntimeException {
 
     /** Exception that might have caused this one. */
-    private Exception cause;
+    private Throwable cause;
 
     /** Location in the build file where the exception occured */
     private Location location = Location.UNKNOWN_LOCATION;
@@ -89,10 +89,10 @@ public class BuildException extends RuntimeException {
      * Constructs an exception with the given message and exception as
      * a root cause.
      * @param msg Description of or information about the exception.
-     * @param cause Exception that might have cause this one.
+     * @param cause Throwable that might have cause this one.
      */
 
-    public BuildException(String msg, Exception cause) {
+    public BuildException(String msg, Throwable cause) {
 	super(msg);
 	this.cause = cause;
     }
@@ -105,7 +105,7 @@ public class BuildException extends RuntimeException {
      * @param location Location in the project file where the error occured.
      */
 
-    public BuildException(String msg, Exception cause, Location location) {
+    public BuildException(String msg, Throwable cause, Location location) {
         this(msg, cause);
 	this.location = location;
     }
@@ -115,7 +115,7 @@ public class BuildException extends RuntimeException {
      * @param cause Exception that might have caused this one.
      */
 
-    public BuildException(Exception cause) {
+    public BuildException(Throwable cause) {
 	super(cause.toString());
 	this.cause = cause;
     }
@@ -135,7 +135,7 @@ public class BuildException extends RuntimeException {
     /**
      * Returns the nested exception.
      */
-    public Exception getException() {
+    public Throwable getException() {
         return cause;
     }
 

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

@@ -222,12 +222,17 @@ public class Main {
         try {
             try {
                 Class.forName("javax.xml.parsers.SAXParserFactory");
+                ProjectHelper.configureProject(project, buildFile);
+            } catch (NoClassDefFoundError ncdfe) {
+                throw new BuildException("No JAXP compliant XML parser found. See http://java.sun.com/xml for the\nreference implementation.", ncdfe);
             } catch (ClassNotFoundException cnfe) {
-                throw new BuildException(cnfe);
+                throw new BuildException("No JAXP compliant XML parser found. See http://java.sun.com/xml for the\nreference implementation.", cnfe);
+            } catch (NullPointerException npe) {
+                throw new BuildException("No JAXP compliant XML parser found. See http://java.sun.com/xml for the\nreference implementation.", npe);
             }
-            ProjectHelper.configureProject(project, buildFile);
         } catch (BuildException be) {
             System.out.println("\nBUILD CONFIG ERROR\n");
+            System.out.println(be.getMessage());
             if (be.getException() == null) {
                 System.out.println(be.toString());
             } else {