code: public String getID() {
          byte[] genBytes = new byte[this.outputSize];
          synchronized (this.generator) {
              this.generator.nextBytes(genBytes);
          }
          String id = convertSessionIdBytesToSessionId(genBytes, this.idLength);
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
              Tr.debug(tc, "getID: " + id);
          }
          return id;
      }
docs: Request the next random ID field from the generator.
  
  @return String