An error message that is supposed to print a method name instead prints 'null' when the error occurs inside of an initializer block.

public class InitializerError {

  int foo() {
    String s = "x";
    String s = "y";
  }

  static int bar() {
    String s = "x";
    String s = "y";
  }

  {
    String s = "x";
    String s = "y";
  }

  static {
    String s = "x";
    String s = "y";
  }

}

Output:

InitializerError.java:5: error: s is already defined in foo()
    String s = "y";
           ^
InitializerError.java:10: error: s is already defined in bar()
    String s = "y";
           ^
InitializerError.java:15: error: s is already defined in null
    String s = "y";
           ^
InitializerError.java:20: error: s is already defined in null
    String s = "y";
           ^
4 errors

In javac 6, the error message was different, but also bad -- it used an empty string as the method name.