src/org/jnetpcap/packet/JPacket.java
public <T extends JHeader> boolean hasHeader(T header, int instance) {
		check();

		final int index = this.state.findHeaderIndex(header.getId(), instance);
		if (index == -1) {
			return false;
		}

		getHeaderByIndex(index, header);

		return true;
	}
/**
	 * Check if requested instance of header with specified numerical ID exists
	 * within the decoded packet and if found peers the supplied header with the
	 * located header within the decoded packet. This method executes as hasHeader
	 * followed by getHeader if found more efficiently.
	 * 
	 * @param <T>
	 *          name of the header type
	 * @param header
	 *          protocol header object instance
	 * @param instance
	 *          instance number of the specific header within the packet
	 * @return true header exists, otherwise false
	 */
Check if requested instance of header with specified numerical ID exists
within the decoded packet and if found peers the supplied header with the
located header within the decoded packet. This method executes as hasHeader
followed by getHeader if found more efficiently.

@param 
name of the header type
@param header
protocol header object instance
@param instance
instance number of the specific header within the packet
@return true header exists, otherwise false
Check if requested instance of header with specified numerical ID exists within the decoded packet and if found peers the supplied header with the located header within the decoded packet . This method executes as hasHeader followed by getHeader if found more efficiently . @param name of the header type @param header protocol header object instance @param instance instance number of the specific header within the packet @return true header exists otherwise false
public <T extends JHeader> boolean hasHeader(T header, int instance) {
		check();
		final int index = this.state.findHeaderIndex(header.getId(), instance);
		if (index == -1) {
			return false;
		}
		getHeaderByIndex(index, header);
		return true;
	}
public < T extends JHeader > boolean hasHeader ( T header , int instance ) { check ( ) ; final int index = this . state . findHeaderIndex ( header . getId ( ) , instance ) ; if ( index == - 1 ) { return false ; } getHeaderByIndex ( index , header ) ; return true ; }
Check if requested instance of header with specified numerical ID exists
 within the decoded packet and if found peers the supplied header with the
 located header within the decoded packet.
Check if requested instance of header with specified numerical ID exists within the decoded packet and if found peers the supplied header with the located header within the decoded packet .