use exceptions for better invalid index error reporting (bug #45957) * lo-array-gripes.h, lo-array-gripes.cc (index_exception): New base class for indexing errors. (invalid_index, out_of_range): New classes. (gripe_index_out_of_range): New overloaded function. (gripe_invalid_index): New overloaded functions. Delete version with no arguments. (gripe_invalid_assignment_size, gripe_assignment_dimension_mismatch): Delete. Change uses of gripe functions as needed. * Cell.cc (Cell::index, Cell::assign, Cell::delete_elements): Use exceptions to collect error info about and handle indexing errors. * data.cc (Fnth_element, do_accumarray_sum, F__accumarray_sum__, do_accumarray_minmax, do_accumarray_minmax_fun, F__accumdim_sum__): Likewise. * oct-map.cc (octave_map::index, octave_map::assign, octave_map::delete_elements): Likewise. * sparse.cc (Fsparse): Likewise. * sub2ind.cc (Fsub2ind, Find2sub): Likewise. New tests. * utils.cc (dims_to_numel): Likewise. * ov-base-diag.cc (octave_base_diag<DMT, MT>::do_index_op, octave_base_diag<DMT, MT>::subsasgn): Likewise. * ov-base-mat.cc (octave_base_matrix<MT>::subsref, octave_base_matrix<MT>::assign): Likewise. * ov-base-sparse.cc (octave_base_sparse<T>::do_index_op, octave_base_sparse<T>::assign, octave_base_sparse<MT>::delete_elements): Likewise. * ov-classdef.cc (cdef_object_array::subsref, cdef_object_array::subsasgn): Likewise. * ov-java.cc (make_java_index): Likewise. * ov-perm.cc (octave_perm_matrix::do_index_op): Likewise. * ov-range.cc (octave_range::do_index_op): Likewise. * ov-re-diag.cc (octave_diag_matrix::do_index_op): Likewise. * ov-str-mat.cc (octave_char_matrix_str::do_index_op_internal): Likewise. * pt-assign.cc (tree_simple_assignment::rvalue1): Likewise. * pt-idx.cc (tree_index_expression::rvalue, tree_index_expression::lvalue): Likewise. * Array-util.cc (sub2ind): Likewise. * toplev.cc (main_loop): Also catch unhandled index_exception exceptions. * ov-base.cc (octave_base_value::index_vector): Improve error message. * ov-re-sparse.cc (octave_sparse_matrix::index_vector): Likewise. * ov-complex.cc (complex_index): New class. (gripe_complex_index): New function. (octave_complex::index_vector): Use it. * pt-id.h, pt-id.cc (tree_identifier::is_variable, tree_black_hole::is_variable): Now const. * pt-idx.cc (final_index_error): New static function. (tree_index_expression::rvalue, tree_index_expression::lvalue): Use it. * index.tst: New tests.

--- a/libinterp/octave-value/ov-java.cc	Fri Oct 02 12:25:39 2015 -0400
+++ b/libinterp/octave-value/ov-java.cc	Fri Oct 02 15:07:37 2015 -0400
@@ -827,28 +827,35 @@
   jobjectArray retval = jni_env->NewObjectArray (idx.length (), ocls, 0);
 
   for (int i = 0; i < idx.length (); i++)
-    {
-      idx_vector v = idx(i).index_vector ();
-
-      if (! error_state)
-        {
-          jintArray_ref i_array (jni_env, jni_env->NewIntArray (v.length ()));
-          jint *buf = jni_env->GetIntArrayElements (i_array, 0);
-
-          for (int k = 0; k < v.length (); k++)
-            buf[k] = v(k);
-
-          jni_env->ReleaseIntArrayElements (i_array, buf, 0);
-          jni_env->SetObjectArrayElement (retval, i, i_array);
-
-          check_exception (jni_env);
-
-          if (error_state)
-            break;
-        }
-      else
-        break;
-    }
+    try
+      {
+        idx_vector v = idx(i).index_vector ();
+
+        if (! error_state)
+          {
+            jintArray_ref i_array (jni_env, jni_env->NewIntArray (v.length ()));
+            jint *buf = jni_env->GetIntArrayElements (i_array, 0);
+
+            for (int k = 0; k < v.length (); k++)
+              buf[k] = v(k);
+
+            jni_env->ReleaseIntArrayElements (i_array, buf, 0);
+            jni_env->SetObjectArrayElement (retval, i, i_array);
+
+            check_exception (jni_env);
+
+            if (error_state)
+              break;
+          }
+        else
+          break;
+      }
+    catch (index_exception& e)
+      {
+        // Rethrow to allow more info to be reported later.
+        e.set_pos_if_unset (idx.length (), i+1);
+        throw;
+      }
 
   return retval;
 }