code: private void initializeVerifier() {
          ManifestEntryVerifier mev = null;
  
          // Verify "META-INF/" entries...
          try {
              String[] names = getMetaInfEntryNames();
              if (names != null) {
                  for (int i = 0; i < names.length; i++) {
                      JarEntry e = getJarEntry(names[i]);
                      if (e == null) {
                          throw new JarException("corrupted jar file");
                      }
                      if (!e.isDirectory()) {
                          if (mev == null) {
                              mev = new ManifestEntryVerifier
                                  (getManifestFromReference());
                          }
                          byte[] b = getBytes(e);
                          if (b != null && b.length > 0) {
                              jv.beginEntry(e, mev);
                              jv.update(b.length, b, 0, b.length, mev);
                              jv.update(-1, null, 0, 0, mev);
                          }
                      }
                  }
              }
          } catch (IOException ex) {
              // if we had an error parsing any blocks, just
              // treat the jar file as being unsigned
              jv = null;
              verify = false;
              if (JarVerifier.debug != null) {
                  JarVerifier.debug.println("jarfile parsing error!");
                  ex.printStackTrace();
              }
          }
  
          // if after initializing the verifier we have nothing
          // signed, we null it out.
  
          if (jv != null) {
  
              jv.doneWithMeta();
              if (JarVerifier.debug != null) {
                  JarVerifier.debug.println("done with meta!");
              }
  
              if (jv.nothingToVerify()) {
                  if (JarVerifier.debug != null) {
                      JarVerifier.debug.println("nothing to verify!");
                  }
                  jv = null;
                  verify = false;
              }
          }
      }
docs: /*
  Initializes the verifier object by reading all the manifest
  entries and passing them to the verifier.