Java obtains 0-9,a-z,a-z range of random numbers

/**
* Java obtains 0-9,a-z,a-z range of random numbers
* @param length random number
* @return String
*/
public static String Getrandomchar (int length) {
char[] chr = {' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', ' 8 ', ' 9 ',
' A ', ' B ', ' C ', ' d ', ' e ', ' f ', ' g ', ' h ', ' I ', ' j ', ' K ', ' l ', ' m ', ' n ', ' o ', ' P ', ' Q ', ' R ', ' s ', ' t ', ' u ', ' V ', ' w ', ' x ', ' Y ' ', ' Z ',
' A ', ' B ', ' C ', ' D ', ' E ', ' F ', ' G ', ' H ', ' I ', ' J ', ' K ', ' L ', ' M ', ' N ', ' O ', ' P ', ' Q ', ' R ', ' S ', ' T ', ' U ', ' V ', ' W ', ' X ', ' Y ' ', ' Z '};
Random random = new random ();
StringBuffer buffer = new StringBuffer ();
for (int i = 0; i < length; i++) {
Buffer.append (Chr[random.nextint (62)]);
}
return buffer.tostring ();
}
public static String Getrandomchar () {
Return Getrandomchar (10);
}

Java obtains 0-9,a-z,a-z range of random numbers