Why Does My Java Code Throw a \'Signer Information Does Not Match\' SecurityException?

Understanding Class Signer Mismatches in Java

Question:

Why do I encounter a SecurityException with the message "class 'XYZ's signer information does not match"?

Answer:

This error typically occurs when different classes within the same package are loaded from JAR files with varying signatures.

Root Cause:

Java's security mechanisms verify the signatures of classes during loading. When a class from a signed JAR is loaded, its signature is compared to the signatures of other loaded classes from the same package. If the signatures do not match, a SecurityException is thrown.

Solutions:

There are two main solutions to resolve this issue:

1. Verify Consistent Signing: Ensure that all JAR files containing classes from the same package have been signed using the same certificate. This will ensure consistent verification of class signatures.
2. Remove Signatures: Alternatively, if signatures are not necessary, remove them from the manifest files of the JARs. By doing so, Java will not attempt to verify the signatures and will bypass the security exception.

The above is the detailed content of Why Does My Java Code Throw a \'Signer Information Does Not Match\' SecurityException?. For more information, please follow other related articles on the PHP Chinese website!