--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.httpclient/share/classes/java/net/http/WSProtocolException.java	Mon May 09 23:33:09 2016 +0100
@@ -0,0 +1,68 @@
+package java.net.http;
+
+import java.net.http.WebSocket.CloseCode;
+
+import static java.net.http.WebSocket.CloseCode.PROTOCOL_ERROR;
+import static java.util.Objects.requireNonNull;
+
+//
+// Special kind of exception closed from the outside world.
+//
+// Used as a "marker exception" for protocol issues in the incoming data, so the
+// implementation could close the connection and specify an appropriate status
+// code.
+//
+// A separate 'section' argument makes it more uncomfortable to be lazy and to
+// leave a relevant spec reference empty :-) As a bonus all messages have the
+// same style.
+//
+final class WSProtocolException extends RuntimeException {
+
+    private static final long serialVersionUID = 1L;
+    private final CloseCode closeCode;
+    private final String section;
+
+    WSProtocolException(String section, String detail) {
+        this(section, detail, PROTOCOL_ERROR);
+    }
+
+    WSProtocolException(String section, String detail, Throwable cause) {
+        this(section, detail, PROTOCOL_ERROR, cause);
+    }
+
+    private WSProtocolException(String section, String detail, CloseCode code) {
+        super(formatMessage(section, detail));
+        this.closeCode = requireNonNull(code);
+        this.section = section;
+    }
+
+    WSProtocolException(String section, String detail, CloseCode code,
+                        Throwable cause) {
+        super(formatMessage(section, detail), cause);
+        this.closeCode = requireNonNull(code);
+        this.section = section;
+    }
+
+    private static String formatMessage(String section, String detail) {
+        if (requireNonNull(section).isEmpty()) {
+            throw new IllegalArgumentException();
+        }
+        if (requireNonNull(detail).isEmpty()) {
+            throw new IllegalArgumentException();
+        }
+        return WSUtils.webSocketSpecViolation(section, detail);
+    }
+
+    CloseCode getCloseCode() {
+        return closeCode;
+    }
+
+    public String getSection() {
+        return section;
+    }
+
+    @Override
+    public String toString() {
+        return super.toString() + "[" + closeCode + "]";
+    }
+}