The utility class to solve the Path Manipulation issue found by the Fortify Static Code Analyzer.

Normalize.java

/**
 * Path Manipulation (Input Validation and Representation, Data Flow)
 *
 * **Abstract:**
 *
 * Attackers are able to control the file system path argument, which allows them to access or
 * modify otherwise protected files.
 *
 * **Explanation:**
 *
 * Path manipulation errors occur when the following two conditions are met:
 *
 * 1. An attacker is able to specify a path used in an operation on the file system.
 *
 * 2. By specifying the resource, the attacker gains a capability that would not otherwise be
 * permitted.
 *
 * For example, the program may give the attacker the ability to overwrite the specified file or run
 * with a configuration controlled by the attacker.
 */

// https://gist.github.com/hkneptune/aed0fa3fc42cb9b84eb40579eaefc95a

package com.neptuneli.util;

public class Normalize {

  private Normalize() {
  }

  /**
   * Remove invalid characters in the string
   *
   * @param  input The string with variables entered by users
   * @return       The clean string
   */
  public static String parse(final String input) {

    final StringBuilder output = new StringBuilder();

    if (input != null) {
      for (int i = 0; i < input.length(); ++i) {
        output.append(Normalize.parse(input.charAt(i)));
      }
    }

    return output.toString();
  }

  /**
   * Replace the character with a valid character
   *
   * @param  input The character for checking
   * @return       The clean character
   */
  public static char parse(final char input) {

    final int digit = (int) input;
    char output = '\0';

    // All
    // for (int i = 32; i <= 126; ++i) {
    // if (digit == i) {
    //     output = (char) i;
    //   }
    // }

    // From 0 to 9 and :
    for (int i = 48; i <= 58; ++i) {
      if (digit == i) {
        output = (char) i;
      }
    }

    // @ and From A to Z
    for (int i = 64; i <= 90; ++i) {
      if (digit == i) {
        output = (char) i;
      }
    }

    // From a to z
    for (int i = 97; i <= 122; ++i) {
      if (digit == i) {
        output = (char) i;
      }
    }

    // - . /
    for (int i = 45; i <= 47; ++i) {
      if (digit == i) {
        output = (char) i;
      }
    }

    // \
    if (digit == 92) {
      output = (char) 92;
    }

    // _
    if (digit == 95) {
      output = (char) 95;
    }

    // space
    if (digit == 32) {
      output = (char) 32;
    }

    return output;
  }
}