Usage: javac <options> <source files>
where possible options include:
  -g                         Generate all debugging info
  -g:none                    Generate no debugging info
  -g:{lines,vars,source}     Generate only some debugging info

public class testDebug{

	public static void main(String[] args){
                final int a=5;
		int x=2;
		int y=3;
		int z=x+y;
		x--;
		y++;
		z=a;
        }

}

Code:
      stack=2, locals=5, args_size=1
         0: iconst_2      
         1: istore_2      
         2: iconst_3      
         3: istore_3      
         4: iload_2       
         5: iload_3       
         6: iadd          
         7: istore        4
         9: iinc          2, -1
        12: iinc          3, 1
        15: iconst_5      
        16: istore        4
        18: return        
      LineNumberTable:
        line 5: 0
        line 6: 2
        line 7: 4
        line 8: 9
        line 9: 12
        line 10: 15
        line 11: 18

// ...... тот же самый код что и в g:lines с добавлением описания локальных переменных.
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
               0      21     0  args   [Ljava/lang/String;
               2      19     1     a   I
               4      17     2     x   I
               6      15     3     y   I
              11      10     4     z   I

c:\java_soft\testDebug>jdb testDebug
Initializing jdb ...
>
>
> stop at 4
Usage: stop at <class>:<line_number> or
       stop in <class>.<method_name>[(argument_type,...)]
> stop at testDebug:4
Deferring breakpoint testDebug:4.
It will be set after the class is loaded.
>
>
> run
run testDebug
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
>
 VM Started: Unable to set deferred breakpoint testDebug:4 : No linenumber information for testDebug.  Try compiling with debugging on.

Stopping due to deferred breakpoint errors.
"thread=main", java.lang.Class.getDeclaredMethods0(), line=-1 bci=-1