Consider the following Java code segment:

public Hashtable countAlphabet(String aString){

Hashtable table = new Hashtable();

If (aString.length > 4000) return table;

StringBuffer buffer = new StringBuffer(aString);

While (buffer.length() > 0){

String firstChar = buffer.substring(0, 1);

Integer count = (Integer)table.get(firstChar);

if (count == null){

count = new Integer(1); }

else{

count = new Integer(count.intValue() + 1);

}

table.put(firstChar, count);

buffer.delete(0, 1);

}

return table;

}

The program counts the numbers of each alphabet in a string, and put the result in a hashtable. Develop a minimum set of test cases that:

1. Guarantees that all independent execution path is exercised at least once;

2. Guarantees that both the true and false side of all logical decisions are exercised;

3. Executes the loop at the boundary values and within the boundaries.