AngstromCTF2016 - Java is the Best (re, 50)

we download   SuperSecure.class  and decompile it using a java de-compiler (jd-gui) :

You get  :

import java.io.PrintStream;

public class SuperSecure
{
  public static void main(String[] paramArrayOfString)
  {
    if ((paramArrayOfString[0].charAt(0) == 'd') && (paramArrayOfString[0].charAt(1) == 'o') && (paramArrayOfString[0].charAt(2) == 'n') && (paramArrayOfString[0].charAt(3) == 't') && (paramArrayOfString[0].charAt(4) == '_') && (paramArrayOfString[0].charAt(5) == 'u') && (paramArrayOfString[0].charAt(6) == 's') && (paramArrayOfString[0].charAt(7) == 'e') && (paramArrayOfString[0].charAt(8) == '_') && (paramArrayOfString[0].charAt(9) == 'j') && (paramArrayOfString[0].charAt(10) == 'a') && (paramArrayOfString[0].charAt(11) == 'v') && (paramArrayOfString[0].charAt(12) == 'a') && (paramArrayOfString[0].charAt(13) == '_') && (paramArrayOfString[0].charAt(14) == 'i') && (paramArrayOfString[0].charAt(15) == 'f') && (paramArrayOfString[0].charAt(16) == '_') && (paramArrayOfString[0].charAt(17) == 'y') && (paramArrayOfString[0].charAt(18) == 'o') && (paramArrayOfString[0].charAt(19) == 'u') && (paramArrayOfString[0].charAt(20) == '_') && (paramArrayOfString[0].charAt(21) == 'w') && (paramArrayOfString[0].charAt(22) == 'a') && (paramArrayOfString[0].charAt(23) == 'n') && (paramArrayOfString[0].charAt(24) == 'n') && (paramArrayOfString[0].charAt(25) == 'a') && (paramArrayOfString[0].charAt(26) == '_') && (paramArrayOfString[0].charAt(27) == 'h') && (paramArrayOfString[0].charAt(28) == 'i') && (paramArrayOfString[0].charAt(29) == 'd') && (paramArrayOfString[0].charAt(30) == 'e') && (paramArrayOfString[0].charAt(31) == '_') && (paramArrayOfString[0].charAt(32) == 'c') && (paramArrayOfString[0].charAt(33) == 'o') && (paramArrayOfString[0].charAt(34) == 'd') && (paramArrayOfString[0].charAt(35) == 'e')) {
      System.out.println("Hooray!");
    }
  }
}

And as you can see the flag is :  dont_use_java_if_you_wanna_hide_code