Store text file content line by line into array

I would recommend using an ArrayList, which handles dynamic sizing, whereas an array will require a defined size up front, which you may not know. You can always turn the list back into an array.

BufferedReader in = new BufferedReader(new FileReader("path/of/text"));
String str;

List<String> list = new ArrayList<String>();
while((str = in.readLine()) != null){
    list.add(str);
}

String[] stringArr = list.toArray(new String[0]);

The simplest solution:

List<String> list = Files.readAllLines(Paths.get("path/of/text"), StandardCharsets.UTF_8);
String[] a = list.toArray(new String[list.size()]); 

Note that java.nio.file.Files is since 1.7