Java, Long.parse binary String

Question

Why does this code throw a NumberFormatException :

String binStr = \"1000000000000000000000000000000000000000000000000000000000000000\";
System         


        

Answer 1

This is the largest possible long (9223372036854775807 = 2 exp 63 - 1) in binary format. Note the L at the end of the last digit.

 long largestLong = 0B0111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111_1111L;