char c3 = '\u00000d'; //valid
This is invalid. The unicode representation should be '\uXXXX' where the four Xs is hexadecimal form. While '\u000a' and '\000d' are valid hex form using it in
java will result in compile-time error. These are newline and carraige return respectively and interpreted by the compiler as line terminator characters.
Different ways for char assignment:
char t = 'a';
ch\0061r t = 'a';
char t = '\0061';
char \u0062 = 'b';
char t = '\n'; // newline
char s = 65;
char m = '\333';
// --> last the last three digits is an octal value which can only be less than 377 (equivalent to first 256 characters including 0).