I ran into a failing test scenario where the Java string logged server-side with the DeprecationLogger.deprecatedAndMaybeLog failed to match the same string when materialized client-side using Response. getWarnings().
The string in question had quotes eg:

public static final String DEPRECATION_MESSAGE = "Don't use \"type\" please";

which is encoded to HTTP headers by the logging framework with slashes around the quotes eg Don't use \"type\" please
When deserialized on the client the slashes are not decoded meaning our test fails because Don't use \"type\" please != Don't use "type" please