java - StringBuilder improperly reversing a filename -

i have stringbuilder used reverse , return string. string in question filename: "server_1.8.2_java_8.jar" (this vary).

when reverse string , return it, becomes "sre_.._aa8jra._vj281rve". i've used variations of (as regular sentences "reverse string") , same result.

however, if directly assign string inside method it's reversed in (rather taking parameter , performing some operations on it), seems work properly.

test method code in case helps:

static string parsejarfilename(string jarlocation) {             if(jarlocation == null)                     return ""; // path jar location empty,                                        // return stuff doesn't messed             string jarfilename = ""; // name of .jar server executable             for(int = jarlocation.length(); jarlocation.charat(i - 1) != '/'; --) {                     // read string backwards until / found,                     // signaling jarfile name has ended                     // done, concatenate characters of jarfile name                     jarfilename += jarlocation.charat(i - 1);                     jarfilename.trim();                     // jarfile name backwards here, reverse                     string str = new stringbuilder(jarfilename).reverse().tostring();                     jarfilename = str;             }             return jarfilename;     }  public static void main(string[] args) {     string filepath = "/users/john/desktop/server/server_1.8.2_java_8.jar";     string filename = parsejarfilename(filepath);     system.out.println(filename); }  // written 2xedo: twitter.com/2xedo 

this code prints "sre_.._aa8jra._vj281rve" console.

if not mistaken looking like

public static string parsejarfilename(string jarlocation) {     if (jarlocation == null)         return "";      return jarlocation.substring(jarlocation.lastindexof('/')+1); } 

or maybe little more readable

public static string parsejarfilename(string jarlocation) {     if (jarlocation == null)         return "";      return new file(jarlocation).getname(); } 

you can use path newer (and in cases preferred) version of file

return paths.get(jarlocation).getfilename().tostring();