title: What does it mean a string is lexicographically greater than another string?
body: <p>I have two strings in java:</p>
  
  <pre><code>s1 = "-7ff9";
  s2 = "-7ff9";
  </code></pre>
  
  <p>I get the s2 string from a response from a server. Instead string s1 is a value of a parameter. 
  When I ask :</p>
  
  <pre><code>if(s1.equals(s2)){ System.out.println("YES");}
  else System.out.println("NO");
  </code></pre>
  
  <p>I get the response <strong>NO</strong>.</p>
  
  <p>I then compared the to strings:</p>
  
  <pre><code>System.out.println(s1.compareTo(s2));
  </code></pre>
  
  <p>I get an  <strong>19</strong> output which means " string s1 is lexicographically greater than the string argument s2"</p>
  
  <p>I just don't know how to solve this ...</p>