equals implementations are not null-safe

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@1554398 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/types/Resource.java

@@ -287,7 +287,8 @@ public class Resource extends DataType implements Comparable<Resource>, Resource
         if (isReference()) {
             return getCheckedRef().equals(other);
         }
-        return other.getClass().equals(getClass()) && compareTo((Resource) other) == 0;
+        return other != null && other.getClass().equals(getClass())
+            && compareTo((Resource) other) == 0;
     }
 
     /**

src/main/org/apache/tools/ant/types/resources/ArchiveResource.java

@@ -216,7 +216,7 @@ public abstract class ArchiveResource extends Resource {
         if (isReference()) {
             return getCheckedRef().equals(another);
         }
-        if (!(another.getClass().equals(getClass()))) {
+        if (another == null || !(another.getClass().equals(getClass()))) {
             return false;
         }
         ArchiveResource r = (ArchiveResource) another;

src/main/org/apache/tools/ant/types/resources/FileResource.java

@@ -299,7 +299,7 @@ public class FileResource extends Resource implements Touchable, FileProvider,
         if (isReference()) {
             return getCheckedRef().equals(another);
         }
-        if (!(another.getClass().equals(getClass()))) {
+        if (another == null || !(another.getClass().equals(getClass()))) {
             return false;
         }
         FileResource otherfr = (FileResource) another;

src/main/org/apache/tools/ant/types/resources/URLResource.java

@@ -298,7 +298,7 @@ public class URLResource extends Resource implements URLProvider {
         if (isReference()) {
             return getCheckedRef().equals(another);
         }
-        if (!(another.getClass().equals(getClass()))) {
+        if (another == null || !(another.getClass().equals(getClass()))) {
             return false;
         }
         URLResource otheru = (URLResource) another;