code: public static boolean JVMSupportsLargeMappedFiles() {
          String arch = System.getProperty("os.arch");
          if(arch==null || !arch.contains("64")) {
              return false;
          }
  
          if(isWindows())
              return false;
  
          //TODO better check for 32bit JVM
          return true;
      }
docs: Check if large files can be mapped into memory.
  For example 32bit JVM can only address 2GB and large files can not be mapped,
  so for 32bit JVM this function returns false.