Support Underscores in Numbers (java7)

long creditCardNumber = 1234_5678_9012_3456L;
long socialSecurityNumbers = 999_99_9999L;
float monetaryAmount = 12_345_132.12;
long hexBytes = 0xFF_EC_DE_5E;
long hexWords = 0xFFEC_DE5E;
long maxLong = 0x7fff_ffff_ffff_ffffL;
long alsoMaxLong = 9_223_372_036_854_775_807L;
double whyWouldYouEverDoThis = 0x1_.ffff_ffff_ffff_fp10_23;

// Additionally, if binary literals are ever added to the Java language, the following might also be possible...
   byte nybbles = 0b0010_0101;
   long bytes = 0b11010010_01101001_10010100_10010010;
   int weirdBitfields = 0b000_10_101;


// Note that according to this proposal, underscores can only be placed between digits. They cannot be placed by themselves in positions where a string of digits would normally be expected:

int x1 = _52;  // This is an identifier, not a numeric literal.
int x2 = 5_2;  // OK. (Decimal literal)
int x2 = 52_;  // Illegal. (Underscores must always be between digits)
int x3 = 5_______2; // OK. (Decimal literal.)

int x4 = 0_x52;  // Illegal. Can't put underscores in the "0x" radix prefix.
int x5 = 0x_52;  // Illegal. (Underscores must always be between digits)
int x6 = 0x5_2;  // OK. (Hexadecimal literal)
int x6 = 0x52_;  // Illegal. (Underscores must always be between digits)
int x6 = 0x_;    // Illegal. (Not valid with the underscore removed)

int x7 = 0_52;   // OK. (Octal literal)
int x7 = 05_2;   // OK. (Octal literal)
int x8 = 052_;   // Illegal. (Underscores must always be between digits)