src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavaTokenizer.java

*** 204,215 ****
          char saveCh;
          int savePos;
          do {
              if (reader.ch != '_') {
                  reader.putChar(false);
-             } else {
-                 checkSourceLevel(pos, Feature.UNDERSCORES_IN_LITERALS);
              }
              saveCh = reader.ch;
              savePos = reader.bp;
              reader.scanChar();
          } while (reader.digit(pos, digitRadix) >= 0 || reader.ch == '_');
--- 204,213 ----
*** 516,526 ****
                      if (reader.ch == 'x' || reader.ch == 'X') {
                          reader.scanChar();
                          skipIllegalUnderscores();
                          scanNumber(pos, 16);
                      } else if (reader.ch == 'b' || reader.ch == 'B') {
-                         checkSourceLevel(pos, Feature.BINARY_LITERALS);
                          reader.scanChar();
                          skipIllegalUnderscores();
                          scanNumber(pos, 2);
                      } else {
                          reader.putChar('0');
--- 514,523 ----