diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/APIServlet.java b/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/APIServlet.java
index d378429..2f4cd2a 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/APIServlet.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/APIServlet.java
@@ -83,29 +83,12 @@
         } catch (ParseException | TokenMgrError | edu.uci.ics.asterix.aqlplus.parser.TokenMgrError pe) {
             GlobalConfig.ASTERIX_LOGGER.log(Level.INFO, pe.toString(), pe);
             out.println("<pre class=\"error\">");
-            String message = pe.getMessage();
-            message = message.replace("<", "&lt");
-            message = message.replace(">", "&gt");
-            out.println("SyntaxError:" + message);
-            int pos = message.indexOf("line");
-            if (pos > 0) {
-                int columnPos = message.indexOf(",", pos + 1 + "line".length());
-                int lineNo = Integer.parseInt(message.substring(pos + "line".length() + 1, columnPos));
-                String[] lines = query.split("\n");
-                if (lineNo >= lines.length) {
-                    out.println("===> &ltBLANK LINE&gt");
-                } else {
-                    String line = lines[lineNo - 1];
-                    out.println("==> " + line);
-                }
-            }
-            out.println("</pre>");
-        } catch (Exception e) {
-            String errorMessage = ResultUtils.extractErrorMessage(e);
-            GlobalConfig.ASTERIX_LOGGER.log(Level.SEVERE, errorMessage, e);
-            out.println("<pre class=\"error\">");
+            String errorMessage = ResultUtils.buildParseExceptionMessage(pe, query);
             out.println(errorMessage);
             out.println("</pre>");
+        } catch (Exception e) {
+            GlobalConfig.ASTERIX_LOGGER.log(Level.SEVERE, e.getMessage(), e);
+            ResultUtils.webUIErrorHandler(out, e);
         }
     }
 
diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/RESTAPIServlet.java b/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/RESTAPIServlet.java
index dff759d..d1b2d5f 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/RESTAPIServlet.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/api/http/servlet/RESTAPIServlet.java
@@ -17,7 +17,6 @@
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.List;
-import java.util.logging.Level;
 
 import javax.servlet.ServletContext;
 import javax.servlet.http.HttpServlet;
@@ -32,8 +31,8 @@
 import edu.uci.ics.asterix.aql.base.Statement.Kind;
 import edu.uci.ics.asterix.aql.parser.AQLParser;
 import edu.uci.ics.asterix.aql.parser.ParseException;
+import edu.uci.ics.asterix.aql.parser.TokenMgrError;
 import edu.uci.ics.asterix.aql.translator.AqlTranslator;
-import edu.uci.ics.asterix.common.config.GlobalConfig;
 import edu.uci.ics.asterix.metadata.MetadataManager;
 import edu.uci.ics.asterix.result.ResultReader;
 import edu.uci.ics.asterix.result.ResultUtils;
@@ -95,28 +94,12 @@
             AqlTranslator aqlTranslator = new AqlTranslator(aqlStatements, out, sessionConfig, format);
 
             aqlTranslator.compileAndExecute(hcc, hds, asyncResults);
-
-        } catch (ParseException pe) {
-            GlobalConfig.ASTERIX_LOGGER.log(Level.INFO, pe.toString(), pe);
-            StringBuilder errorMessage = new StringBuilder();
-            String message = pe.getLocalizedMessage();
-            message = message.replace("<", "&lt");
-            message = message.replace(">", "&gt");
-            errorMessage.append("SyntaxError:" + message + "\n");
-            int pos = message.indexOf("line");
-            if (pos > 0) {
-                int columnPos = message.indexOf(",", pos + 1 + "line".length());
-                int lineNo = Integer.parseInt(message.substring(pos + "line".length() + 1, columnPos));
-                String line = query.split("\n")[lineNo - 1];
-                errorMessage.append("==> " + line + "\n");
-            }
-            JSONObject errorResp = ResultUtils.getErrorResponse(2, errorMessage.toString());
+        } catch (ParseException | TokenMgrError | edu.uci.ics.asterix.aqlplus.parser.TokenMgrError pe) {
+            String errorMessage = ResultUtils.buildParseExceptionMessage(pe, query);
+            JSONObject errorResp = ResultUtils.getErrorResponse(2, errorMessage);
             out.write(errorResp.toString());
         } catch (Exception e) {
-            String errorMessage = ResultUtils.extractErrorMessage(e);
-            GlobalConfig.ASTERIX_LOGGER.log(Level.SEVERE, errorMessage, e);
-            JSONObject errorResp = ResultUtils.getErrorResponse(99, errorMessage);
-            out.write(errorResp.toString());
+            ResultUtils.apiErrorHandler(out, e);
         }
     }
 
diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java b/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java
index 911f6fd..5f12fe2 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/aql/translator/AqlTranslator.java
@@ -186,112 +186,107 @@
             metadataProvider.setOutputFile(outputFile);
             metadataProvider.setConfig(config);
             jobsToExecute.clear();
-            try {
-                switch (stmt.getKind()) {
-                    case SET: {
-                        handleSetStatement(metadataProvider, stmt, config);
-                        break;
-                    }
-                    case DATAVERSE_DECL: {
-                        activeDefaultDataverse = handleUseDataverseStatement(metadataProvider, stmt);
-                        break;
-                    }
-                    case CREATE_DATAVERSE: {
-                        handleCreateDataverseStatement(metadataProvider, stmt);
-                        break;
-                    }
-                    case DATASET_DECL: {
-                        handleCreateDatasetStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case CREATE_INDEX: {
-                        handleCreateIndexStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case TYPE_DECL: {
-                        handleCreateTypeStatement(metadataProvider, stmt);
-                        break;
-                    }
-                    case NODEGROUP_DECL: {
-                        handleCreateNodeGroupStatement(metadataProvider, stmt);
-                        break;
-                    }
-                    case DATAVERSE_DROP: {
-                        handleDataverseDropStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case DATASET_DROP: {
-                        handleDatasetDropStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case INDEX_DROP: {
-                        handleIndexDropStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case TYPE_DROP: {
-                        handleTypeDropStatement(metadataProvider, stmt);
-                        break;
-                    }
-                    case NODEGROUP_DROP: {
-                        handleNodegroupDropStatement(metadataProvider, stmt);
-                        break;
-                    }
-
-                    case CREATE_FUNCTION: {
-                        handleCreateFunctionStatement(metadataProvider, stmt);
-                        break;
-                    }
-
-                    case FUNCTION_DROP: {
-                        handleFunctionDropStatement(metadataProvider, stmt);
-                        break;
-                    }
-
-                    case LOAD_FROM_FILE: {
-                        handleLoadFromFileStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case WRITE_FROM_QUERY_RESULT: {
-                        handleWriteFromQueryResultStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case INSERT: {
-                        handleInsertStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-                    case DELETE: {
-                        handleDeleteStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-
-                    case BEGIN_FEED: {
-                        handleBeginFeedStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-
-                    case CONTROL_FEED: {
-                        handleControlFeedStatement(metadataProvider, stmt, hcc);
-                        break;
-                    }
-
-                    case QUERY: {
-                        metadataProvider.setResultSetId(new ResultSetId(resultSetIdCounter++));
-                        executionResult.add(handleQuery(metadataProvider, (Query) stmt, hcc, hdc, asyncResults));
-                        break;
-                    }
-
-                    case WRITE: {
-                        Pair<IAWriterFactory, FileSplit> result = handleWriteStatement(metadataProvider, stmt);
-                        if (result.first != null) {
-                            writerFactory = result.first;
-                        }
-                        outputFile = result.second;
-                        break;
-                    }
-
+            switch (stmt.getKind()) {
+                case SET: {
+                    handleSetStatement(metadataProvider, stmt, config);
+                    break;
                 }
-            } catch (Exception e) {
-                throw new AlgebricksException(e);
+                case DATAVERSE_DECL: {
+                    activeDefaultDataverse = handleUseDataverseStatement(metadataProvider, stmt);
+                    break;
+                }
+                case CREATE_DATAVERSE: {
+                    handleCreateDataverseStatement(metadataProvider, stmt);
+                    break;
+                }
+                case DATASET_DECL: {
+                    handleCreateDatasetStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case CREATE_INDEX: {
+                    handleCreateIndexStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case TYPE_DECL: {
+                    handleCreateTypeStatement(metadataProvider, stmt);
+                    break;
+                }
+                case NODEGROUP_DECL: {
+                    handleCreateNodeGroupStatement(metadataProvider, stmt);
+                    break;
+                }
+                case DATAVERSE_DROP: {
+                    handleDataverseDropStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case DATASET_DROP: {
+                    handleDatasetDropStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case INDEX_DROP: {
+                    handleIndexDropStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case TYPE_DROP: {
+                    handleTypeDropStatement(metadataProvider, stmt);
+                    break;
+                }
+                case NODEGROUP_DROP: {
+                    handleNodegroupDropStatement(metadataProvider, stmt);
+                    break;
+                }
+
+                case CREATE_FUNCTION: {
+                    handleCreateFunctionStatement(metadataProvider, stmt);
+                    break;
+                }
+
+                case FUNCTION_DROP: {
+                    handleFunctionDropStatement(metadataProvider, stmt);
+                    break;
+                }
+
+                case LOAD_FROM_FILE: {
+                    handleLoadFromFileStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case WRITE_FROM_QUERY_RESULT: {
+                    handleWriteFromQueryResultStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case INSERT: {
+                    handleInsertStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+                case DELETE: {
+                    handleDeleteStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+
+                case BEGIN_FEED: {
+                    handleBeginFeedStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+
+                case CONTROL_FEED: {
+                    handleControlFeedStatement(metadataProvider, stmt, hcc);
+                    break;
+                }
+
+                case QUERY: {
+                    metadataProvider.setResultSetId(new ResultSetId(resultSetIdCounter++));
+                    executionResult.add(handleQuery(metadataProvider, (Query) stmt, hcc, hdc, asyncResults));
+                    break;
+                }
+
+                case WRITE: {
+                    Pair<IAWriterFactory, FileSplit> result = handleWriteStatement(metadataProvider, stmt);
+                    if (result.first != null) {
+                        writerFactory = result.first;
+                    }
+                    outputFile = result.second;
+                    break;
+                }
             }
         }
         return executionResult;
@@ -364,7 +359,7 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             abort(e, e, mdTxnCtx);
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -528,7 +523,7 @@
                 }
             }
 
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -664,7 +659,7 @@
                             + "." + datasetName + "." + indexName + ") couldn't be removed from the metadata", e);
                 }
             }
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -703,7 +698,7 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             abort(e, e, mdTxnCtx);
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -817,7 +812,7 @@
                 }
             }
 
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -922,7 +917,7 @@
                 }
             }
 
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -1027,7 +1022,7 @@
                 }
             }
 
-            throw new AlgebricksException(e);
+            throw e;
 
         } finally {
             releaseWriteLatch();
@@ -1054,7 +1049,7 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             abort(e, e, mdTxnCtx);
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -1080,7 +1075,7 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             abort(e, e, mdTxnCtx);
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -1106,7 +1101,7 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             abort(e, e, mdTxnCtx);
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -1130,7 +1125,7 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             abort(e, e, mdTxnCtx);
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -1178,7 +1173,7 @@
                 abort(e, e, mdTxnCtx);
             }
 
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseReadLatch();
         }
@@ -1208,7 +1203,7 @@
             if (bActiveTxn) {
                 abort(e, e, mdTxnCtx);
             }
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseReadLatch();
         }
@@ -1241,7 +1236,7 @@
             if (bActiveTxn) {
                 abort(e, e, mdTxnCtx);
             }
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseReadLatch();
         }
@@ -1275,7 +1270,7 @@
             if (bActiveTxn) {
                 abort(e, e, mdTxnCtx);
             }
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseReadLatch();
         }
@@ -1341,7 +1336,7 @@
             if (bActiveTxn) {
                 abort(e, e, mdTxnCtx);
             }
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseReadLatch();
         }
@@ -1370,7 +1365,7 @@
             if (bActiveTxn) {
                 abort(e, e, mdTxnCtx);
             }
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseReadLatch();
         }
@@ -1401,28 +1396,38 @@
                     handle.put(jobId.getId());
                     handle.put(metadataProvider.getResultSetId().getId());
                     response.put("handle", handle);
+                    out.print(response);
+                    out.flush();
                 } else {
+                    if (pdf == DisplayFormat.HTML) {
+                        out.println("<pre>");
+                    }
+
                     ByteBuffer buffer = ByteBuffer.allocate(ResultReader.FRAME_SIZE);
                     ResultReader resultReader = new ResultReader(hcc, hdc);
                     resultReader.open(jobId, metadataProvider.getResultSetId());
                     buffer.clear();
-                    JSONArray results = new JSONArray();
+
                     while (resultReader.read(buffer) > 0) {
-                        results.put(ResultUtils.getJSONFromBuffer(buffer, resultReader.getFrameTupleAccessor()));
+                        response.put("results",
+                                ResultUtils.getJSONFromBuffer(buffer, resultReader.getFrameTupleAccessor()));
                         buffer.clear();
+                        switch (pdf) {
+                            case HTML:
+                                ResultUtils.prettyPrintHTML(out, response);
+                                break;
+                            case TEXT:
+                            case JSON:
+                                out.print(response);
+                                break;
+                        }
+                        out.flush();
                     }
-                    response.put("results", results);
-                }
-                switch (pdf) {
-                    case HTML:
-                        out.println("<pre>");
-                        ResultUtils.prettyPrintHTML(out, response);
+
+                    if (pdf == DisplayFormat.HTML) {
                         out.println("</pre>");
-                        break;
-                    case TEXT:
-                    case JSON:
-                        out.print(response);
-                        break;
+                    }
+
                 }
                 hcc.waitForCompletion(jobId);
             }
@@ -1433,7 +1438,7 @@
             if (bActiveTxn) {
                 abort(e, e, mdTxnCtx);
             }
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseReadLatch();
         }
@@ -1463,7 +1468,7 @@
             MetadataManager.INSTANCE.commitTransaction(mdTxnCtx);
         } catch (Exception e) {
             abort(e, e, mdTxnCtx);
-            throw new AlgebricksException(e);
+            throw e;
         } finally {
             releaseWriteLatch();
         }
@@ -1502,8 +1507,7 @@
         return format;
     }
 
-    private String getActiveDataverseName(String dataverse)
-            throws AlgebricksException {
+    private String getActiveDataverseName(String dataverse) throws AlgebricksException {
         if (dataverse != null) {
             return dataverse;
         }
@@ -1512,13 +1516,11 @@
         }
         throw new AlgebricksException("dataverse not specified");
     }
-    
-    private String getActiveDataverseName(Identifier dataverse)
-            throws AlgebricksException {
-        return getActiveDataverseName(
-                dataverse != null ? dataverse.getValue() : null);
+
+    private String getActiveDataverseName(Identifier dataverse) throws AlgebricksException {
+        return getActiveDataverseName(dataverse != null ? dataverse.getValue() : null);
     }
-    
+
     private void acquireWriteLatch() {
         MetadataManager.INSTANCE.acquireWriteLatch();
     }
@@ -1543,4 +1545,4 @@
             throw new IllegalStateException(rootE);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/asterix-app/src/main/java/edu/uci/ics/asterix/result/ResultUtils.java b/asterix-app/src/main/java/edu/uci/ics/asterix/result/ResultUtils.java
index 02cf6a4..8354160 100644
--- a/asterix-app/src/main/java/edu/uci/ics/asterix/result/ResultUtils.java
+++ b/asterix-app/src/main/java/edu/uci/ics/asterix/result/ResultUtils.java
@@ -17,11 +17,16 @@
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.nio.ByteBuffer;
+import java.util.logging.Level;
 
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import com.sun.el.parser.ParseException;
+
+import edu.uci.ics.asterix.common.config.GlobalConfig;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
 import edu.uci.ics.hyracks.api.comm.IFrameTupleAccessor;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.dataflow.common.comm.util.ByteBufferInputStream;
@@ -80,6 +85,73 @@
         }
     }
 
+    public static void webUIErrorHandler(PrintWriter out, Exception e) {
+        String errPrefix = "";
+        if (e instanceof AlgebricksException) {
+            errPrefix = "Compilation error: ";
+        } else if (e instanceof HyracksDataException) {
+            errPrefix = "Runtime error: ";
+        }
+
+        Throwable cause = getRootCause(e);
+
+        GlobalConfig.ASTERIX_LOGGER.log(Level.SEVERE, e.getMessage(), e);
+        out.println("<pre class=\"error\">");
+        out.println(errPrefix + cause.getMessage());
+        out.println("</pre>");
+    }
+
+    public static void apiErrorHandler(PrintWriter out, Exception e) {
+        int errorCode = 99;
+        String errPrefix = "";
+        if (e instanceof ParseException) {
+            errorCode = 2;
+        } else if (e instanceof AlgebricksException) {
+            errorCode = 3;
+            errPrefix = "Compilation error: ";
+        } else if (e instanceof HyracksDataException) {
+            errorCode = 4;
+            errPrefix = "Runtime error: ";
+        }
+
+        Throwable cause = getRootCause(e);
+
+        GlobalConfig.ASTERIX_LOGGER.log(Level.SEVERE, e.getMessage(), e);
+        JSONObject errorResp = ResultUtils.getErrorResponse(errorCode, errPrefix + cause.getMessage());
+        out.write(errorResp.toString());
+    }
+
+    public static String buildParseExceptionMessage(Throwable e, String query) {
+        GlobalConfig.ASTERIX_LOGGER.log(Level.INFO, e.toString(), e);
+        StringBuilder errorMessage = new StringBuilder();
+        String message = e.getMessage();
+        message = message.replace("<", "&lt");
+        message = message.replace(">", "&gt");
+        errorMessage.append("SyntaxError:" + message + "\n");
+        int pos = message.indexOf("line");
+        if (pos > 0) {
+            int columnPos = message.indexOf(",", pos + 1 + "line".length());
+            int lineNo = Integer.parseInt(message.substring(pos + "line".length() + 1, columnPos));
+            String[] lines = query.split("\n");
+            if (lineNo >= lines.length) {
+                errorMessage.append("===> &ltBLANK LINE&gt \n");
+            } else {
+                String line = lines[lineNo - 1];
+                errorMessage.append("==> " + line);
+            }
+        }
+        return errorMessage.toString();
+    }
+
+    private static Throwable getRootCause(Throwable cause) {
+        Throwable nextCause = cause.getCause();
+        while (nextCause != null) {
+            cause = nextCause;
+            nextCause = cause.getCause();
+        }
+        return cause;
+    }
+
     /**
      * extract meaningful part of a stack trace:
      * a. the causes in the stack trace hierarchy