output: #fixed code
                                  @Test
      public void testIPv6Check() throws UnknownHostException {
          InetAddress nonInternal = InetAddress.getByName("2408:4004:0180:8100:3FAA:1DDE:2B3F:898A");
          InetAddress internal = InetAddress.getByName("FE80:0000:0000:0000:0000:0000:0000:FFFF");
          assertThat(UtilAll.isInternalV6IP(nonInternal)).isFalse();
          assertThat(UtilAll.isInternalV6IP(internal)).isTrue();
          assertThat(UtilAll.ipToIPv6Str(nonInternal.getAddress()).toUpperCase()).isEqualTo("2408:4004:0180:8100:3FAA:1DDE:2B3F:898A");
      }
input: #vulnerable code 
                                  @Test
      public void testIPv6Check() {
          byte[] nonInternalIp = UtilAll.string2bytes("24084004018081003FAA1DDE2B3F898A");
          byte[] internalIp = UtilAll.string2bytes("FEC0000000000000000000000000FFFF");
          assertThat(UtilAll.isInternalV6IP(nonInternalIp)).isFalse();
          assertThat(UtilAll.isInternalV6IP(internalIp)).isTrue();
          assertThat(UtilAll.ipToIPv6Str(nonInternalIp).toUpperCase()).isEqualTo("2408:4004:0180:8100:3FAA:1DDE:2B3F:898A");
      } 
                              #location 6 
                              #vulnerability type NULL_DEREFERENCE