Split string into sentences

It will be difficult to get a regular expression to work in all cases, but to fix your immediate problem you can use a lookbehind:

String sResult = "This is a test. This is a T.L.A. test.";
String[] sSentence = sResult.split("(?<=[a-z])\\.\\s+");

Result:

This is a test
This is a T.L.A. test.

Note that there are abbrevations that do not end with capital letters, such as abbrev., Mr., etc... And there are also sentences that don't end in periods!

Parsing sentences is far from being a trivial task, even for latin languages like English. A naive approach like the one you outline in your question will fail often enough that it will prove useless in practice.

A better approach is to use a BreakIterator configured with the right Locale.

BreakIterator iterator = BreakIterator.getSentenceInstance(Locale.US);
String source = "This is a test. This is a T.L.A. test. Now with a Dr. in it.";
iterator.setText(source);
int start = iterator.first();
for (int end = iterator.next();
    end != BreakIterator.DONE;
    start = end, end = iterator.next()) {
  System.out.println(source.substring(start,end));
}

Yields the following result:

1. This is a test.
2. This is a T.L.A. test.
3. Now with a Dr. in it.