--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,12 @@
 # ChangeLog file for monetdb-java
 # This file is updated with Maddlog
 
+* Thu Aug 31 2017 Martin van Dinther <martin.van.dinther@monetdbsolutions.com>
+- Corrected PreparedStatement methods setString(int, String)
+  and setObject(int, Object, ...) in case the target parameter
+  data type was json or inet or url or uuid.  See also
+  https://www.monetdb.org/bugzilla/show_bug.cgi?id=6382
+
 * Thu Aug 24 2017 Martin van Dinther <martin.van.dinther@monetdbsolutions.com>
 - Implemented PreparedStatement method setURL(int, URL).
 - Implemented PreparedStatement method setNString(int, String).

--- a/src/main/java/nl/cwi/monetdb/jdbc/MonetPreparedStatement.java
+++ b/src/main/java/nl/cwi/monetdb/jdbc/MonetPreparedStatement.java
@@ -62,7 +62,7 @@ import java.util.Map;
  *
  * @author Fabian Groffen
  * @author Martin van Dinther
- * @version 0.4
+ * @version 0.5
  */
 public class MonetPreparedStatement
 	extends MonetStatement
@@ -1773,118 +1773,7 @@ public class MonetPreparedStatement
 
 		// this is according to table B-5
 		if (x instanceof String) {
-			switch (targetSqlType) {
-				case Types.CHAR:
-				case Types.VARCHAR:
-				case Types.LONGVARCHAR:
-				case Types.CLOB:
-					setString(parameterIndex, (String)x);
-				break;
-				case Types.TINYINT:
-				case Types.SMALLINT:
-				case Types.INTEGER:
-				{
-					int val;
-					try {
-						val = Integer.parseInt((String)x);
-					} catch (NumberFormatException e) {
-						val = 0;
-					}
-					setInt(parameterIndex, val);
-				} break;
-				case Types.BIGINT:
-				{
-					long val;
-					try {
-						val = Long.parseLong((String)x);
-					} catch (NumberFormatException e) {
-						val = 0;
-					}
-					setLong(parameterIndex, val);
-				} break;
-				case Types.REAL:
-				{
-					float val;
-					try {
-						val = Float.parseFloat((String)x);
-					} catch (NumberFormatException e) {
-						val = 0;
-					}
-					setFloat(parameterIndex, val);
-				} break;
-				case Types.FLOAT:
-				case Types.DOUBLE:
-				{
-					double val;
-					try {
-						val = Double.parseDouble((String)x);
-					} catch (NumberFormatException e) {
-						val = 0;
-					}
-					setDouble(parameterIndex, val);
-				} break;
-				case Types.DECIMAL:
-				case Types.NUMERIC:
-				{
-					BigDecimal val;
-					try {
-						val = new BigDecimal((String)x);
-					} catch (NumberFormatException e) {
-						try {
-							val = new BigDecimal(0.0);
-						} catch (NumberFormatException ex) {
-							throw new SQLException("Internal error: unable to create template BigDecimal: " + ex.getMessage(), "M0M03");
-						}
-					}
-					val = val.setScale(scale, BigDecimal.ROUND_HALF_UP);
-					setBigDecimal(parameterIndex, val);
-				} break;
-				case Types.BIT:
-				case Types.BOOLEAN:
-					setBoolean(parameterIndex, (Boolean.valueOf((String)x)).booleanValue());
-				break;
-				case Types.BINARY:
-				case Types.VARBINARY:
-				case Types.LONGVARBINARY:
-					setBytes(parameterIndex, ((String)x).getBytes());
-				break;
-				case Types.DATE:
-				{
-					java.sql.Date val;
-					try {
-						val = java.sql.Date.valueOf((String)x);
-					} catch (IllegalArgumentException e) {
-						val = new java.sql.Date(0L);
-					}
-					setDate(parameterIndex, val);
-				} break;
-				case Types.TIME:
-				{
-					Time val;
-					try {
-						val = Time.valueOf((String)x);
-					} catch (IllegalArgumentException e) {
-						val = new Time(0L);
-					}
-					setTime(parameterIndex, val);
-				} break;
-				case Types.TIMESTAMP:
-				{
-					Timestamp val;
-					try {
-						val = Timestamp.valueOf((String)x);
-					} catch (IllegalArgumentException e) {
-						val = new Timestamp(0L);
-					}
-					setTimestamp(parameterIndex, val);
-				} break;
-				case Types.NCHAR:
-				case Types.NVARCHAR:
-				case Types.LONGNVARCHAR:
-					throw newSQLFeatureNotSupportedException("setObject() with targetType N[VAR]CHAR");
-				default:
-					throw new SQLException("Conversion not allowed", "M1M05");
-			}
+			setString(parameterIndex, (String)x);
 		} else if (x instanceof BigDecimal ||
 				x instanceof Byte ||
 				x instanceof Short ||
@@ -2090,9 +1979,9 @@ public class MonetPreparedStatement
 			}
 		} else if (x instanceof Array) {
 			setArray(parameterIndex, (Array)x);
-		} else if (x instanceof Blob) {
+		} else if (x instanceof Blob || x instanceof MonetBlob) {
 			setBlob(parameterIndex, (Blob)x);
-		} else if (x instanceof Clob) {
+		} else if (x instanceof Clob || x instanceof MonetClob) {
 			setClob(parameterIndex, (Clob)x);
 		} else if (x instanceof Struct) {
 			// I have no idea how to do this...
@@ -2101,6 +1990,8 @@ public class MonetPreparedStatement
 			setRef(parameterIndex, (Ref)x);
 		} else if (x instanceof java.net.URL) {
 			setURL(parameterIndex, (java.net.URL)x);
+		} else if (x instanceof java.util.UUID) {
+			setString(parameterIndex, x.toString());
 		} else if (x instanceof RowId) {
 			setRowId(parameterIndex, (RowId)x);
 		} else if (x instanceof NClob) {
@@ -2256,7 +2147,7 @@ public class MonetPreparedStatement
 			};
 			sx.writeSQL(out);
 		} else {	// java Class
-			throw newSQLFeatureNotSupportedException("setObject() with object of type Class");
+			throw newSQLFeatureNotSupportedException("setObject() with object of type Class " + x.getClass().getName());
 		}
 	}
 
@@ -2322,10 +2213,164 @@ public class MonetPreparedStatement
 			return;
 		}
 
-		setValue(
-			parameterIndex,
-			"'" + x.replaceAll("\\\\", "\\\\\\\\").replaceAll("'", "\\\\'") + "'"
-		);
+		int paramIdx = getParamIdx(parameterIndex);	// this will throw a SQLException if parameter can not be found
+
+		/* depending on the parameter data type (as expected by MonetDB) we
+		   may need to add the data type as cast prefix to the parameter value */
+		int paramJdbcType = javaType[paramIdx];
+		String paramMonetdbType = monetdbType[paramIdx];
+
+		switch (paramJdbcType) {
+			case Types.CHAR:
+			case Types.VARCHAR:
+			case Types.LONGVARCHAR:
+			case Types.CLOB:
+			case Types.NCHAR:
+			case Types.NVARCHAR:
+			case Types.LONGNVARCHAR:
+			{
+				String castprefix = "";
+				switch (paramMonetdbType) {
+					// some MonetDB specific data types require a cast prefix
+					case "inet":
+						try {
+							// check if x represents a valid inet string to prevent
+							// failing exec #(..., ...) calls which destroy the prepared statement, see bug 6351
+							nl.cwi.monetdb.jdbc.types.INET inet_obj = new nl.cwi.monetdb.jdbc.types.INET();
+							inet_obj.fromString(x);
+						} catch (SQLException se) {
+							throw new SQLException("Conversion of string: " + x + " to parameter data type " + paramMonetdbType + " failed. " + se, "M1M05");
+						}
+						castprefix = "inet ";
+						break;
+					case "json":
+						// There is no support for JSON in standard java class libraries.
+						// Possibly we could use org.json.simple.JSONObject or other/faster libs
+						// javax.json.Json is not released yet (see https://json-processing-spec.java.net/)
+						// see also https://github.com/fabienrenaud/java-json-benchmark
+						// Note that it would make our JDBC driver dependent of an external jar
+						// and we don't want that.
+
+						// do simplistic check if x represents a valid json string to prevent
+						// failing exec #(..., ...) calls which destroy the prepared statement, see bug 6351
+						if (x.isEmpty() ||
+							(x.startsWith("{") && !x.endsWith("}")) ||
+							(x.startsWith("[") && !x.endsWith("]"))
+							// TODO check completely if x represents a valid json string
+						   )
+							throw new SQLException("Invalid json string. It does not start with { or [ and end with } or ]", "M1M05");
+
+						// TODO check completely if x represents a valid json string
+
+						castprefix = "json ";
+						break;
+					case "url":
+						try {
+							// also check if x represents a valid url string to prevent
+							// failing exec #(..., ...) calls which destroy the prepared statement, see bug 6351
+							java.net.URL url_obj = new java.net.URL(x);
+						} catch (java.net.MalformedURLException mue) {
+							throw new SQLException("Conversion of string: " + x + " to parameter data type " + paramMonetdbType + " failed. " + mue, "M1M05");
+						}
+						castprefix = "url ";
+						break;
+					case "uuid":
+						try {
+							// also check if x represents a valid uuid string to prevent
+							// failing exec #(..., ...) calls which destroy the prepared statement, see bug 6351
+							java.util.UUID uuid_obj = java.util.UUID.fromString(x);
+						} catch (IllegalArgumentException iae) {
+							throw new SQLException("Conversion of string: " + x + " to parameter data type " + paramMonetdbType + " failed. " + iae, "M1M05");
+						}
+						castprefix = "uuid ";
+						break;
+				}
+				/* in specific cases prefix the string with: inet or json or url or uuid */
+				setValue(parameterIndex,
+					castprefix + "'" + x.replaceAll("\\\\", "\\\\\\\\").replaceAll("'", "\\\\'") + "'");
+				break;
+			}
+			case Types.TINYINT:
+			case Types.SMALLINT:
+			case Types.INTEGER:
+			case Types.BIGINT:
+			case Types.REAL:
+			case Types.FLOAT:
+			case Types.DOUBLE:
+			case Types.DECIMAL:
+			case Types.NUMERIC:
+				try {
+					// check (by calling parse) if the string represents a valid number to prevent
+					// failing exec #(..., ...) calls which destroy the prepared statement, see bug 6351
+					if (paramJdbcType == Types.INTEGER || paramJdbcType == Types.SMALLINT || paramJdbcType == Types.TINYINT) {
+						int number = Integer.parseInt(x);
+					} else
+					if (paramJdbcType == Types.BIGINT) {
+						long number = Long.parseLong(x);
+					} else
+					if (paramJdbcType == Types.REAL || paramJdbcType == Types.DOUBLE || paramJdbcType == Types.FLOAT) {
+						double number = Double.parseDouble(x);
+					} else
+					if (paramJdbcType == Types.DECIMAL || paramJdbcType == Types.NUMERIC) {
+						BigDecimal number = new BigDecimal(x);
+					}
+				} catch (NumberFormatException nfe) {
+					throw new SQLException("Conversion of string: " + x + " to parameter data type " + paramMonetdbType + " failed. " + nfe, "M1M05");
+				}
+				setValue(parameterIndex, x);
+				break;
+			case Types.BIT:
+			case Types.BOOLEAN:
+				if  (x.equalsIgnoreCase("false") || x.equalsIgnoreCase("true") || x.equals("0") || x.equals("1")) {
+					setValue(parameterIndex, x);
+				} else {
+					throw new SQLException("Conversion of string: " + x + " to parameter data type " + paramMonetdbType + " failed", "M1M05");
+				}
+				break;
+			case Types.DATE:
+			case Types.TIME:
+			case Types.TIMESTAMP:
+				try {
+					// check if the string represents a valid calendar date or time or timestamp to prevent
+					// failing exec #(..., ...) calls which destroy the prepared statement, see bug 6351
+					if (paramJdbcType == Types.DATE) {
+						java.sql.Date datum = java.sql.Date.valueOf(x);
+					} else
+					if (paramJdbcType == Types.TIME) {
+						Time tijdstip = Time.valueOf(x);
+					} else
+					if (paramJdbcType == Types.TIMESTAMP) {
+						Timestamp tijdstip = Timestamp.valueOf(x);
+					}
+				} catch (IllegalArgumentException iae) {
+					throw new SQLException("Conversion of string: " + x + " to parameter data type " + paramMonetdbType + " failed. " + iae, "M1M05");
+				}
+				/* prefix the string with: date or time or timetz or timestamp or timestamptz */
+				setValue(parameterIndex, paramMonetdbType + " '" + x + "'");
+				break;
+			case Types.BINARY:
+			case Types.VARBINARY:
+			case Types.LONGVARBINARY:
+			case Types.BLOB:
+				// check if the string x contains pairs of hex chars to prevent
+				// failing exec #(..., ...) calls which destroy the prepared statement, see bug 6351
+				int xlen = x.length();
+				for (int i = 0; i < xlen; i++) {
+					char c = x.charAt(i);
+					if (c < '0' || c > '9') {
+						if (c < 'A' || c > 'F') {
+							if (c < 'a' || c > 'f') {
+								throw new SQLException("Invalid string for parameter data type " + paramMonetdbType + ". The string may contain only hex chars", "M1M05");
+							}
+						}
+					}
+				}
+				/* prefix the string with: blob */
+				setValue(parameterIndex, "blob '" + x + "'");
+				break;
+			default:
+				throw new SQLException("Conversion of string to parameter data type " + paramMonetdbType + " is not (yet) supported", "M1M05");
+		}
 	}
 
 	/**

new file mode 100644
--- /dev/null
+++ b/tests/Bug_PrepStmtSetString_6382.java
@@ -0,0 +1,146 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0.  If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 1997 - July 2008 CWI, August 2008 - 2017 MonetDB B.V.
+ */
+
+import java.sql.*;
+import nl.cwi.monetdb.jdbc.types.INET;
+import nl.cwi.monetdb.jdbc.types.URL;
+
+public class Bug_PrepStmtSetString_6382 {
+	public static void main(String[] args) throws Exception {
+		// Class.forName("nl.cwi.monetdb.jdbc.MonetDriver");	// not needed anymore for self registering JDBC drivers
+		Connection con = DriverManager.getConnection(args[0]);
+		System.out.println("0. true\t" + con.getAutoCommit());
+
+		Statement stmt = null;
+		PreparedStatement pstmt = null;
+		ParameterMetaData pmd = null;
+		ResultSet rs = null;
+		ResultSetMetaData rsmd = null;
+		try {
+			stmt = con.createStatement();
+			String tableName = "PrepStmtSetString_6382";
+			System.out.println("Creating table " + tableName);
+			stmt.executeUpdate("CREATE TABLE " + tableName + " (myint INT, myvarchar VARCHAR(15), myjson JSON, myuuid UUID, myurl URL, myinet INET)");
+
+			System.out.println("Inserting row 1");
+			stmt.executeUpdate("INSERT INTO " + tableName + " VALUES (1, 'row 1', '{}', uuid '34c8deb5-e608-406b-beda-6a951f73d455', 'https://www.monetdb.org/', '128.0.0.1')");
+
+			System.out.println("Inserting row 2");
+			stmt.executeUpdate("INSERT INTO " + tableName + " VALUES (2, 'row 2', '[]', NULL, NULL, NULL)");
+
+
+			System.out.println("Creating a prepared statement with 6 parameters and inserting rows using setInt(), setString(), setNull(), setNString(), setURL(), setObject().");
+			pstmt = con.prepareStatement("INSERT INTO " + tableName + " VALUES (?,?, ? ,?,? , ?)");
+			pmd = pstmt.getParameterMetaData();
+			int pcount = pmd.getParameterCount();
+			System.out.println("Prepared Statement has " + pcount + " parameters:" + (pcount != 6 ? " ERROR: Expected 6 parameters!" : ""));
+			for (int p = 1; p <= pcount; p++) {
+				System.out.println(" Parameter " + p + " type is: " + pmd.getParameterTypeName(p) + ". JDBC SQL type: " + pmd.getParameterType(p));
+			}
+
+			int row = 3;
+			pstmt.setInt(1, row);
+			pstmt.setString(2, "row " + row);
+			pstmt.setString(3, "{\"menu\": {\n  \"id\": \"file\",\n  \"value\": \"File\",\n  \"popup\": {\n    \"menuitem\": [\n      {\"value\": \"New\", \"onclick\": \"CreateNewDoc()\"},\n      {\"value\": \"Open\", \"onclick\": \"OpenDoc()\"},\n      {\"value\": \"Close\", \"onclick\": \"CloseDoc()\"}\n    ]\n  }\n}}");
+			pstmt.setNull(4, 0);
+			pstmt.setNull(5, 0);
+			pstmt.setNull(6, 0);
+			System.out.println("Inserting row " + row);
+			int inserted = pstmt.executeUpdate();
+			System.out.println("Inserted " + inserted + " row");
+
+			row++;  // row 4
+			pstmt.setShort(1, (short)row);
+			pstmt.setNString(2, "row " + row);
+			pstmt.setNull(3, 0);
+			pstmt.setString(4, "4a148b7d-8d47-4e1e-a21e-09a71abf2215");
+			System.out.println("Inserting row " + row);
+			inserted = pstmt.executeUpdate();
+			System.out.println("Inserted " + inserted + " row");
+
+			row++;  // row 5
+			pstmt.setLong(1, row);
+			pstmt.setString(2, "row " + row);
+			pstmt.setNull(4, 0);
+			pstmt.setURL(5, new java.net.URL("https://www.cwi.nl/"));
+			System.out.println("Inserting row " + row);
+			inserted = pstmt.executeUpdate();
+			System.out.println("Inserted " + inserted + " row");
+
+			row++;  // row 6
+			pstmt.setBigDecimal(1, new java.math.BigDecimal(row));
+			pstmt.setNString(2, "row " + row);
+			pstmt.setNull(5, 0);
+			pstmt.setString(6, "127.255.255.255");
+			System.out.println("Inserting row " + row);
+			inserted = pstmt.executeUpdate();
+			System.out.println("Inserted " + inserted + " row");
+
+			/* also test generic setObject(int, String) */
+			row++;  // row 7
+			pstmt.setObject(1, new Integer(row));
+			pstmt.setObject(2, "row " + row);
+			pstmt.setObject(3, "{\"menu\": {\n    \"header\": \"SVG Viewer\",\n    \"items\": [\n        {\"id\": \"Open\"},\n        {\"id\": \"OpenNew\", \"label\": \"Open New\"},\n        null,\n        {\"id\": \"ZoomIn\", \"label\": \"Zoom In\"},\n        {\"id\": \"ZoomOut\", \"label\": \"Zoom Out\"},\n        {\"id\": \"OriginalView\", \"label\": \"Original View\"},\n        null,\n        {\"id\": \"Quality\"},\n        {\"id\": \"Pause\"},\n        {\"id\": \"Mute\"},\n        null,\n        {\"id\": \"Help\"},\n        {\"id\": \"About\", \"label\": \"About Adobe CVG Viewer...\"}\n    ]\n}}");
+			pstmt.setObject(4, "b39dc76e-4faf-4fd9-bc1e-17df48acf764");
+			pstmt.setObject(5, "https://en.wikipedia.org/wiki/IP_address");
+			pstmt.setObject(6, "223.255.255.255");
+			System.out.println("Inserting row " + row);
+			inserted = pstmt.executeUpdate();
+			System.out.println("Inserted " + inserted + " row");
+
+			row++;  // row 8
+			pstmt.setObject(1, new java.math.BigDecimal(row));
+			pstmt.setObject(2, "row " + row);
+			pstmt.setObject(3, null);
+			pstmt.setObject(4, java.util.UUID.fromString("ff125769-b63c-4c3c-859f-5b84a9349e24"));
+			URL myURL = new URL();
+			myURL.fromString("https://en.wikipedia.org/wiki/IP_address");
+			pstmt.setObject(5, myURL);
+			INET myINET = new INET();
+			myINET.fromString("223.234.245.255");
+			pstmt.setObject(6, myINET);
+			System.out.println("Inserting row " + row);
+			inserted = pstmt.executeUpdate();
+			System.out.println("Inserted " + inserted + " row");
+
+
+			System.out.println("List contents of TABLE " + tableName + " after " + row + " rows inserted");
+			rs = stmt.executeQuery("SELECT * FROM " + tableName + " ORDER BY 1");
+			rsmd = rs.getMetaData();
+			int colcount = rsmd.getColumnCount();
+			System.out.println("Query has " + colcount + " output columns." + (colcount != 6 ? " ERROR: Expected 6 columns!" : ""));
+			row = 0;
+			while (rs.next()) {
+				System.out.print("row " + ++row);
+				for (int c = 1; c <= colcount; c++) {
+					System.out.print("\t" + rs.getString(c));
+				}
+				System.out.println();
+			}
+
+			System.out.println();
+			System.out.println("Cleanup TABLE " + tableName);
+			stmt.executeUpdate("DROP TABLE " + tableName);
+			System.out.println("Test completed successfully");
+		} catch (SQLException e) {
+			System.err.println("FAILED :( "+ e.getMessage());
+			while ((e = e.getNextException()) != null)
+				System.err.println("FAILED :( " + e.getMessage());
+			System.err.println("ABORTING TEST!!!");
+		} finally {
+			if (rs != null)
+				rs.close();
+			if (pstmt != null)
+				pstmt.close();
+			if (stmt != null)
+				stmt.close();
+			con.close();
+		}
+	}
+}
+

--- a/tests/build.xml
+++ b/tests/build.xml
@@ -136,6 +136,7 @@ Copyright 1997 - July 2008 CWI, August 2
     <antcall target="BugResultSetMetaData_Bug_6183" />
     <antcall target="Bug_PrepStmtSetObject_CLOB_6349" />
     <antcall target="Bug_Connect_as_voc_getMetaData_Failure_Bug_6388" />
+    <antcall target="Bug_PrepStmtSetString_6382" />
   </target>
 
   <target name="test_class" depends="compile,jdbc">
@@ -397,4 +398,10 @@ Copyright 1997 - July 2008 CWI, August 2
     </antcall>
   </target>
 
+  <target name="Bug_PrepStmtSetString_6382">
+    <antcall target="test_class">
+      <param name="test.class" value="Bug_PrepStmtSetString_6382" />
+    </antcall>
+  </target>
+
 </project>