code: public static File createTempFile(String prefix, String suffix) {
          String p = System.getProperty(ND4JSystemProperties.ND4J_TEMP_DIR_PROPERTY);
          try {
              if (p == null || p.isEmpty()) {
                  return File.createTempFile(prefix, suffix);
              } else {
                  return File.createTempFile(prefix, suffix, new File(p));
              }
          } catch (IOException e){
              throw new RuntimeException("Error creating temporary file", e);
          }
      }
docs: Create a temporary file in the location specified by {@link ND4JSystemProperties#ND4J_TEMP_DIR_PROPERTY} if set,
  or the default temporary directory (usually specified by java.io.tmpdir system property)
  @param prefix Prefix for generating file's name; must be at least 3 characeters
  @param suffix Suffix for generating file's name; may be null (".tmp" will be used if null)
  @return A temporary file