Non-english letters in Java source code

Rules for defining identifiers in Java:
1. An identifier is composed of a sequence of letters, digits, the currency symbol $ and the separator character _.
2. An identifier cannot start with a digit.
3. An identifier cannot be a reserved from the Java language.

This is not different from the rules in the C programming language. The difference is of the character set used by the programming language. Java uses the Unicode character set and hance the letters and the digits used here are not restricted to the letters and digits available from the ASCII character set, which is used in the C programming language. In Java the letters and digits from any language can be used for example, anyone can use अ (the devanagari letter A, unicode code point value +U0905) in an identifier. The question arises as how can we use these characters in our java source code while using an editor which supports only ascii files. In java source code one can use the unicode escape to specify any unicode character. A unicode escape is written as \uhhhh where hhhh are the four hexadecimal digits for the unicode code unit according to UTF-16. The java compiler would first interpret these unicode escapes before identifying the lines and tokens from the source code. The following are a few interesting examples:

char \u0905 = '\u0905'; is a valid code where the variable named अ (devanagari letter A) is assigned the value 0905(hex).

char ch = '\u000A'; is not valid since the unicode escape \u000A is a new line character and would be seen follows:

char ch = '
';

Thus creating a compilation error. anyone can easily obfuscate the source code by using the unicode escapes for space and semicolon characters, this will make the code totally unreadable.

Currently most of the programmers use the letters and digits from the english language in defining the identifiers. It may be worth trying to create obfuscators which could change the identifiers to non-english letters and digits.

Worthiness of Java Certification

I have been conducting technical interviews for a software company in Vadodara. While conducting the interviews, I found that there are a lot of experienced Java Programmers, who have got nice scores in the Java Certification exams(SCJP), but do not know the basics. A few of them, when questioned about their certification, simply replied that they just prepared from the Kathy Sierra and Bert Bates book and that is the secret of their good score. Most of them failed to answer questions relating to checked and unchecked exceptions, and had no clue about threads. They had wrong concepts related to the use of synchronized keyword. What is the use of such certification, which can be obtained by just mugging up the question and answers from a book.