title: Java SecurityException: signer information does not match
body: <p>I recompiled my classes as usual, and suddenly got the following error message. Why? How can I fix it?</p>
  
  <pre><code>java.lang.SecurityException: class "Chinese_English_Dictionary"'s signer information does not match signer information of other classes in the same package
      at java.lang.ClassLoader.checkCerts(ClassLoader.java:776)
  </code></pre>