code: static public final String format1ForSource(String s) {
          StringBuilder buffer = new StringBuilder();
          buffer.append("\"");
          for (int i=0; i<s.length();) {
              char c = s.charAt(i++);
              if (c < '\u0020' || c == '"' || c == '\\') {
                  if (c == '\n') {
                      buffer.append("\\n");
                  } else if (c == '\t') {
                      buffer.append("\\t");
                  } else if (c == '\r') {
                      buffer.append("\\r");
                  } else {
                      // Represent control characters, backslash and double quote
                      // using octal notation; otherwise the string we form
                      // won't compile, since Unicode escape sequences are
                      // processed before tokenization.
                      buffer.append('\\');
                      buffer.append(HEX_DIGIT[(c & 0700) >> 6]); // HEX_DIGIT works for octal
                      buffer.append(HEX_DIGIT[(c & 0070) >> 3]);
                      buffer.append(HEX_DIGIT[(c & 0007)]);
                  }
              }
              else if (c <= '\u007E') {
                  buffer.append(c);
              }
              else {
                  buffer.append("\\u");
                  buffer.append(HEX_DIGIT[(c & 0xF000) >> 12]);
                  buffer.append(HEX_DIGIT[(c & 0x0F00) >> 8]);
                  buffer.append(HEX_DIGIT[(c & 0x00F0) >> 4]);
                  buffer.append(HEX_DIGIT[(c & 0x000F)]);
              }
          }
          buffer.append('"');
          return buffer.toString();
      }
docs: Format a String for representation in a source file.  Like
  formatForSource but does not do line breaking.