If possible try to join multiple strings and send them in one go. When joining couple of Stings use StringBuffer instead of String. For Example in the above scenario, the initial length of the StringBuffer is set to 50. To avoid this over head declare the approximate size of StringBuffer initially. Also don't over allocate.
Memory is precious at runtime.
Don't try to convert Strings to upper or lower case for String comparison. It adds another level of comparison while performing String comparison. But that power is not required for HTTP transactions most of the times. StringTokenizer is one of the most popularly used function in Java. It really gives the flexibility of parsing Strings with parsing capability of multiple string length delimiter.