If your token and its POS tag is separated by space :
public class FileLinkList{
public static void main(String[] args) {
BufferedReader br = null;
LinkedList<String> list = new LinkedList<String>();
String word;
try {
String sCurrentLine;
br = new BufferedReader(new FileReader("LEXICON.txt"));
while ((sCurrentLine = br.readLine()) != null) {
System.out.println(sCurrentLine);
word = sCurrentLine.trim().split(" ")[0];
list.add(word.toLowerCase());
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null)
br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}