Question

According to Orcale’s Java7 assert guide:

• source mode 1.3 (default) — the compiler accepts programs that use assert as an identifier, but issues warnings. In this mode, programs are not permitted to use the assert statement.
• source mode 1.4 — the compiler generates an error message if the program uses assert as an identifier. In this mode, programs are permitted to use the assert statement.

I wrote such class:

package mm;

public class ClassTest {
    public static void main(String[] arg) {
        int assert = 1;
        System.out.println(assert);
    }
}

It should compile fine if Oracle’s info right (1.3 is default source mode). But I got errors like this:

$ javac -version
javac 1.7.0_04

$ javac -d bin src/mm/*
src\mm\ClassTest.java:5: error: as of release 1.4, 'assert' is a keyword, and may not be used as an identifier
                int assert = 1;
                    ^
  (use -source 1.3 or lower to use 'assert' as an identifier)
src\mm\ClassTest.java:6: error: as of release 1.4, 'assert' is a keyword, and may not be used as an identifier
                System.out.println(assert);
                                   ^
  (use -source 1.3 or lower to use 'assert' as an identifier)
2 errors

I added manually -source 1.3 and it issued warnings but compiled fine. It seems that Oracle’s information is wrong and 1.3 is not default source mode. Which one is it then?

Answer 1

In Java 7, the default source mode is 1.7 according to Oracle’s doc (see the -source option).
The doc you’re referring to probably needs to be updated