the runtime.getWarnings().warnDeprecated(name) call was sometimes used as if it was passed a "message"
... which leads to deprecated warnings such as jruby -v -e 'puts lambda(&proc {})' :

jruby 9.4.0.0 (3.1.0) 2022-11-23 95c0ec159f OpenJDK 64-Bit Server VM 11.0.14.1+1 on 11.0.14.1+1 +jit [x86_64-linux]
-e:1: warning: lambda without a literal block is deprecated; use the proc without lambda instead is deprecated
#<Proc:0x68d6f48e -e:1>

(not the " is deprecated" at the end - added by the warnDeprecated(String) invocation)

reviewed all places using warnDeprecated(String) and started using an warnDeprecated(ID, String) overload which passes the message - this means some places also have a better ID tag (although it isn't used that much).