question: public void writeLineNumberTable ( Environment env , DataOutputStream out , ConstantPool tab ) throws IOException { long ln = - 1 ; int count = 0 ; for ( Instruction inst = first ; inst != null ; inst = inst . next ) { long n = ( inst . where > > WHEREOFFSETBITS ) ; if ( ( n > 0 ) && ( ln != n ) ) { ln = n ; count ++ ; } } ln = - 1 ; out . writeShort ( count ) ; for ( Instruction inst = first ; inst != null ; inst = inst . next ) { long n = ( inst . where > > WHEREOFFSETBITS ) ; if ( ( n > 0 ) && ( ln != n ) ) { ln = n ; out . writeShort ( inst . pc ) ; out . writeShort ( ( int ) ln ) ; } } }
target:  Write the linenumber table